Same File publishes differently for colleague

One of my colleagues has been making revisions to an eLearning I created. He did a “save as” and renamed the file. The edits were very minor (he changed one word in a text box on a few slides). There are four knowledge check slides at the end of the course, where the learner answers using drop-down menus to select answers on each slide.  They have to select one option from each drop-down in order for the SUBMIT button to be enabled, and when they do,  it branches them to the appropriate feedback layer.

No changes were made to the triggers or general function of any of these slides. I’ve double checked it against the original project file to be sure. But for some reason, every time he previews or publishes the file, the SUBMIT button remains disabled even though an answer has been selected from all the required drop-downs. However, when I preview and publish the file, everything works perfectly. This occurs on all four of those knowledge check slides. We both preview/publish the exact same storyline file, but mine works and his does not.

We are using different releases of Storyline 360, as I’ve had to revert back to an earlier version due to the mess that was created with the whole accessibility “feature” that was implemented with scrolling textboxes. He’s using the most recent release date of storyline 360.  That's the only explanation I can think of.  Still, he's made updates to several of my projects, and this has never happened before.  I’m baffled by what could be causing this. Anyone have any ideas?