Not sure if I would call this a bug but make a workflow issue....
as an admin setup an artist with a free subscription account
put the user back to a normal account so they can upgrade
login as the user and try to create a new subscription
result: user gets a message they will be credited for any difference
Then they get an error message trying to continue
I found out after you change the account you need to refresh the cache or it will not go through.
updated by @dazed: 04/09/17 09:32:47AM