It’s not a bug… Depending on when you deleted your account you may not have had to type the following new message:
I affirm that I, [name], wish to delete my account. I understand that deleting my account blocks my ability to login to Streamtip and prevents me from sending tips to other users.
It seems that 99% of the people removing accounts do not read what was above the deletion text box:
You will not be able to login again after deleting your account.
You will not be able to send PayPal tips to other streamers after deleting your account.
You must login with Twitch to send tips in order for us to prevent abusive users. If you opt to delete your account, then we cannot allow you to use the service.
As stated in the FAQ: