You can call another job in the build flow with, for example:
build( "somejob", parameter1: (params.local-parameter), parameter2:"astring" )

Which works fine if 'somejob' has those 2 build parameters. But, if 'somejob' has 3 parameters, and you call it with the above command, the job will sit in the 'pending' state permanently, and will block all other jobs on that jenkins instance. It won't reset until you restart the jenkins controller node. We use worker nodes, this may or may not occur on a single-node system.

The fix is to add the missing parameter to the build command. But it would be much nicer if the job would just take whatever default it might have for that parameter and run, instead of requiring the build flow job to pass it in.