What is this message?

One of my players has had this message on the bottom of his screen for the last two sessions: [character name]: repeating_proficiencies_-MRI23lvii4Lss4miwExz_output Everything seems to be working fine otherwise, but we're still wondering what this means.  This particular player has two characters in this game, this message/error only refers to one of them. Any ideas?

Sounds like a dragged and dropped macro bar button from a sheet that had its button deleted.  They can drag it off the bar and it will delete.  

DM Eddie said: Sounds like a dragged and dropped macro bar button from a sheet that had its button deleted.  They can drag it off the bar and it will delete.   Thanks, DM Eddie!  I'll pass that along.