Correct. However:

Be aware that Citi these days will open a card for you even though you may be denied the bonus. And that does reset your 18 month clock. Only being denied for the card itself doesn't reset your 18 month clock.

So don't count on being denied for the card. If you apply for a card in violation of the 18 month clock, you're quite likely to get approved even if they're not planning to give you any bonus.

This is different from how Citi used to work. As recently as a year or so ago, they would always deny you if they weren't going to give you a bonus. Not any more, though.