Introducing 1h in a schedule textarea input, the following backtrace was generated:

line 1:3: expecting 'o', found '<EOF>'
 at hudson.scheduler.CrontabLexer.nextToken(CrontabLexer.java:184)
 at antlr.TokenBuffer.fill(TokenBuffer.java:69)
 at antlr.TokenBuffer.LA(TokenBuffer.java:80)
 at antlr.LLkParser.LA(LLkParser.java:52)
 at antlr.Parser.match(Parser.java:210)
 at hudson.scheduler.CrontabParser.term(CrontabParser.java:225)
 at hudson.scheduler.CrontabParser.expr(CrontabParser.java:180)
 at hudson.scheduler.CrontabParser.startRule(CrontabParser.java:58)
 at hudson.scheduler.CronTab.set(CronTab.java:118)
 at hudson.scheduler.CronTab.<init>(CronTab.java:100)
 at hudson.scheduler.CronTabList.create(CronTabList.java:121)
Caused: antlr.ANTLRException: Invalid input: "1h"
 at hudson.scheduler.CronTabList.create(CronTabList.java:123)
 at hudson.scheduler.CronTabList.create(CronTabList.java:96)
 at hudson.triggers.Trigger.<init>(Trigger.java:170)
 at hudson.triggers.SCMTrigger.<init>(SCMTrigger.java:107)
 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
 at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
 at java.lang.reflect.Constructor.newInstance(Unknown Source)
 at org.kohsuke.stapler.RequestImpl.invokeConstructor(RequestImpl.java:529)
Caused: java.lang.IllegalArgumentException
 at org.kohsuke.stapler.RequestImpl.invokeConstructor(RequestImpl.java:544)
 at org.kohsuke.stapler.RequestImpl.instantiate(RequestImpl.java:783)
 at org.kohsuke.stapler.RequestImpl.access$200(RequestImpl.java:83)
 at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:678)
Caused: java.lang.IllegalArgumentException: Failed to instantiate class hudson.triggers.SCMTrigger from {"scmpoll_spec":"1h","ignorePostCommitHooks":false}
 at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:680)
 at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:478)
 at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:474)
 at hudson.model.Descriptor.newInstance(Descriptor.java:592)
Caused: java.lang.Error: Failed to instantiate class hudson.triggers.SCMTrigger from {"scmpoll_spec":"1h","ignorePostCommitHooks":false}
 at hudson.model.Descriptor.newInstance(Descriptor.java:600)
 at hudson.model.Descriptor$NewInstanceBindInterceptor.onConvert(Descriptor.java:669)
 at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:621)
 at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:478)
 at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:474)
 at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:695)
 at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:478)
 at org.kohsuke.stapler.RequestImpl.instantiate(RequestImpl.java:777)
 at org.kohsuke.stapler.RequestImpl.access$200(RequestImpl.java:83)
 at org.kohsuke.stapler.RequestImpl$TypePair.convertJSON(RequestImpl.java:678)
 at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:478)
 at org.kohsuke.stapler.RequestImpl.bindJSON(RequestImpl.java:474)
 at hudson.model.Descriptor.newInstance(Descriptor.java:592)
 at hudson.model.JobPropertyDescriptor.newInstance(JobPropertyDescriptor.java:72)
 at hudson.model.JobPropertyDescriptor.newInstance(JobPropertyDescriptor.java:45)
 at hudson.util.DescribableList.rebuild(DescribableList.java:177)
 at hudson.model.Job.doConfigSubmit(Job.java:1305)
 at java.lang.invoke.MethodHandle.invokeWithArguments(Unknown Source)
 at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:343)
 at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:52)
 at org.kohsuke.stapler.PreInvokeInterceptedFunction.invoke(PreInvokeInterceptedFunction.java:26)
 at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:184)
 at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:117)
 at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:129)
 at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
 at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:715)
Caused: javax.servlet.ServletException
 at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:765)
 at org.kohsuke.stapler.Stapler.invoke(Stapler.java:845)
 at org.kohsuke.stapler.MetaClass$5.doDispatch(MetaClass.java:248)
 at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
 at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:715)
 at org.kohsuke.stapler.Stapler.invoke(Stapler.java:845)
 at org.kohsuke.stapler.MetaClass$5.doDispatch(MetaClass.java:248)
 at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
 at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:715)
 at org.kohsuke.stapler.Stapler.invoke(Stapler.java:845)
 at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649)
 at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
 at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:812)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)
 at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:135)
 at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:138)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
 at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:80)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
 at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:117)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:92)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
 at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67)
 at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
 at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:90)
 at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
 at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
 at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
 at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
 at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
 at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
 at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:553)
 at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
 at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
 at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
 at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
 at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
 at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
 at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
 at org.eclipse.jetty.server.Server.handle(Server.java:499)
 at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)
 at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
 at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544)
 at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
 at java.lang.Thread.run(Unknown Source)