Cant make my party have more than 10 members

So I have run into this issue, and I don’t know why but every time I add more than 10 heartlings to a party they don’t all follow any kind of commands together. I am running Alpha 17 develop-3023 (x64). I have attatched my save file. (9.7 MB)

I figured out remaking the party is a quick fix when this bug arises.