We started migrating our Jenkins jobs to pipeline jobs and our build status emails stopped working.
SMTP configuration is working OK I received test email and non pipeline jobs are still sending emails.

If I do something like this

node {
    mail body: 'test', subject: 'test', to: 'ppolivka@xxx.com'
}

Email not sent.

I start digging into mailer plugin and figured out how emails work.
I did some basic debugging out in pipeline code

node {
    def transportClass = javax.mail.Session.getDefaultInstance(java.lang.System.getProperties(), (javax.mail.Authenticator)null).getTransport(new javax.mail.internet.InternetAddress("ppolivka@xxx.com")).getClass();
    echo transportClass.toString();
    mail body: 'test', subject: 'test', to: 'ppolivka@xxx.com'
}

and figured out that email transporter used in this instance is org.jvnet.mock_javamail.MockTransport

[Pipeline] {
[Pipeline] echo
class org.jvnet.mock_javamail.MockTransport
[Pipeline] mail
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
Finished: SUCCESS

Again emails are working fine in non pipeline jobs. Configuration to use MockTransport is going from mock-javamail.jar based on classpath scanning. Is is possible that pipeline exposes this test jar to the classpath somehow?

Is there any easy workaround this configuration?