Haha, are you amazed that coins coming from a legit exchange are flagged as dirty? That's how blockchain analysis works. All these AML scores and tags are bullshit, their algorithm doesn't work and I have a doubt that they tag transactions randomly to make it appear like their algorithm works and when you give them proof that your funds are clean and come from a legit source, they apologize and say that it was a false positive.
I've actually encountered something similar. I provided evidence that my bitcoins came from an exchange, and the recipient (the P2P exchange platform Bitpapa) apologized for the misunderstanding and accepted the bitcoins by transferring them from the deposit address to their storage address. This surprised me, as it either meant that the AML tag was removed, or Bitpapa 'stained' their storage. Today, it became clear that the tag was unlikely removed. When I tried to transfer bitcoins from the Bybit exchange to Bitpapa's address, Bybit's compliance department warned of a high-risk level for that address, and attempting further transfers to any addresses of the same entity could result in a ban. Moreover, the Kraken exchange, from which my initial flagged transfer was made, seems to be facing a surge in complaints. Previously, their support responded within minutes, but now the response time has increased, and a query from December 11 remains unanswered.
Overall, I'm concerned that if Webmixer and other mixers openly claim to facilitate withdrawals from exchange addresses, AML services may be forced to deem all exchange addresses as high-risk.