I had a max lvl Bane
I levelled a Bane costume to max
Now I have just levelled a 2nd Bane
The costume bonus is not applying to him
I do have 2 extra unlevelled Bane costumes
I suspect if I feed the unlevelled Bane costumes to my Li Xiu costume then it will work? I can try it.
As a former software developer this seems very much like a bug to me. 1 costume is supposed to apply to all heroes but clearly it isn’t always working. If you want me to try feeding the unlevelled Bane costumes away I can report the results back.