I created a homebrew background and rather than starting from scratch I started with the Gladiator background.  I wanted to change the tool proficiencies and even though I removed the modifier for musical instruments from the Tool Proficiencies section it is still an option for the the character that adds the background in my campaign.  So now that character has the new options I was able to add successfully, and also the original option that I don't know how to remove. 

 I've tried:

• adding the proficiency back on to the background and then removing it a second time
• changing the characters background to something else and then back to the Homebrew background
• created a copy of the homebrew background to see if the issue is present in both versions

 Has anyone else experienced an issue like this?  If so, how did you resolve it?

The only other thing I can think of at this point is start a completely new background from scratch.  I'm hoping to avoid duplicating work.

Thank you for any help you can provide.