I am getting duplicates of my homebrew subclass when I go to add the multiclass and when I do, I get duplicates of the homebrew spells that I made to be specific to that subclass.  If I don't click on the correct one, I get the error code listed in the title.  This does not happen when I use this homebrew subclass on a new character; it just happens when I do this on a character in the campaign I'm playing in.

Have you published, and re-published those since you created that character?

It's all private, never-been-published stuff.  Do you think there could be some weird interaction going on with the content sharing of my campaign?

I don’t know. Post a link to your character so a Moderator can look at it for you.

Good point, here's a link to the character I'm having this issue with.  I see deleted homebrew spells of mine in the character builder with him too.  Thanks!

https://ddb.ac/characters/24125200/blwkO2