Periodically, I see this notice appear in the JS panel.
This icon prompts me to investigate the block nearest to the error first. Sometimes, I can see something obvious but if not so I test each block via jshint - if you ignore the "undefined variable" warning, it's a helpful tool.
When jshint yields nothing I start looking for an extra space, an open comment, or something else. Today I see nothing. I applied the latest form update today and the app package is the latest. The errors were not present before the update.
Thoughts?