DFPlayer MP3 Player Mini plays track when stop is called

I am using the DFPlayer MP3 Player Mini with an Arduino UNO project and it's exhibiting some strange behavior.  Sometimes it plays with dfPlayer.mp3Folder(1) other times it won't play a file that is called with play until dfPlayer.stop() is called. And this is entirely inconsistent.

I suspect the behavior and inconsistency comes from me uploading new versions of the code to the Arduino while the DFPlayer Mini is already in use so it loses track of what it is playing or not.

I would think there must be a way to totally stop or reset the state of the DFPlayer and play a new track somehow.

I could share my code but I wanted to first see if this seemed like a common, familiar problem that experienced users already know the answer to.