But we are entering a from measure as part of the workflow for event editor. It's happening on two separate routes and we are able to edit other routes in the same event editor session.
It could be a few things causing that error message to appear. Since it's only occurring on two routes and not others, it could be data specific. I would suggest logging a case with Esri Support and they can work to troubleshoot with you to figure out the cause and how to fix it.
