Yes. I already did upthread. Segwit was activated by redefining what was initially an anyonecanspend transaction into a Segwit transaction. A 51% attacker can revert to the old rules. This would make Segwit outputs anyonecanspend outputs. To the extent that a 51(plus)% miner can roll back the chain, the Segwit transactions formerly included in the now-orphaned blocks are now free transactions. Those free transactions that were Segwit are now (again, assuming a reversion to the previous consensus rules) anyonecanspend transactions. The value in the outputs of these anyonecanspend transactions are free to be gobbled up by the 51% miner by including them in a block, and claiming them to themselves.

This ability for a 51% miner to siphon up value is unique to Segwit. It is a novel attack enabled only by the security-impairing so-called 'soft fork' activation method that was employed by The SegWit Omnibus Changeset.

But this is all elementary. We've been over this dozens of times, since the so-called 'soft fork' activation methodology was first proposed. If this is new news, then you have not been participating in the widely-held discussions.

(Indeed, if this be new news, you may have isolated yourself within a core-dominated echo chamber)