My sister was added as AU as well last year and when we checked her first credit report they were still reporting after she was removed from the cards, why report cards that arent even yours idk but it bothers knowing that they are reporting hahha, anyway so the ONLY way they were removed was by disputing them which took about 20-30 days. Thats how my sister removd her AU accounts from report.
What i found is that its the CRAs that dont want to remove the trade line reporting. even if the creditor wants it removed, the CRAs seem to want nothing more than to keep info on you. Another thought is the CRAs like to remain the most relevent out of the tree agencies so, it would seem to benefit them to keep the most infomation on us. my two cents.