Yes, but 99% of blocks will still accept them, and I'm confident they will update it too once the dust settles

So in your opinion is Sparrow’s join compromised? And if so what join do you recommend?

Yes it’s all part of zerolink protocol Tx0 is not a coinjoin txn! Because op_return is not used in coinjoin tx but rather in tx0(transaction zero), which is not a coinjoin txn! Also Tx0 fees are paid to the software publisher, not to the coordinator and no fee is paid during mixing, except fees that paid to miners. then tx goes to premix/postmix which belongs to your own derivation path. Therefore op_return contains info allowing the server to verify that the fee was actually paid to an address., because sending to whirlpool means sending to your own hardened derivation path that you control. It's an anti-spoofing mechanism. If the fee is not seen in the blockchain then the inputs are not registered. It also allows to not use a static fee for address collection. The use of op return in tx0 resilient to potential coordinator failure and enable decentralization - two things a coordinator database can't solve.

WabiSabi coinjoins are far superior to Whirlpool coinjoins. You get complete privacy on your entire balance, there is no "bad bank" that makes your transactions traceable like Whirlpool. WabiSabi coinjoins are available in Wasabi Wallet, BTCPay Server, and Trezor.

You realize you don't need OP_RETURN to coinjoin right?

Kortik, what are you talking about?... Samourai reuses addresses for fee collection, tx0 does nothing to stop that:

GitLab

Coordinator Fee Address Reuse (#462) · Issues · Wallet / samourai-wallet-android · GitLab

For Whirlpool coinjoins, the coordinator collects their fee in each preceding tx0 transaction with its own dedicated output. The value of the fee o...