In Jira 3.13.2, a jira:TransitionWorkflow tag allowed transitions that have a screen with the resolution field, even when the resolution was not specified in the TransitionWorkflow tag. This worked when issue had a resolution set and when it didn't have it.

JRA-16112 fixed the situation where the resolution was not set, and Jelly allowed the transition to occur. It seems that in fixing that bug, we removed the ability of the TransitionWorkflow to transition if the resolution was already defined. I think the Jelly should allow the transition if the resolution was already set.