Unfortunately this is no good news for solving the lower bits puzzle transactions if I understand correctly:
If ALL unconfirmed transactions in mempool are RBF enabled there will a overbidding fight for lower bit-puzzles even if initial transaction has set "NO RBF".
People will watch the mempool, check for solved puzzle publickey, sove it quickly with pollard kangaroo and create a new transaction with higher fee.

Can someone confirm?