This made me laugh, but it's genuinely useful to flag for new Frenchie owners — the breed is smart enough to pick up on exactly this kind of pattern fast. Good that you caught it for what it is rather than rewarding it further. Vet-confirmed fine is the right standard to go back to if you're ever unsure again.

Seen this exact pattern in working dogs too, though usually with a different trigger than a paw bump. It's less "manipulation" in a calculated sense and more a learned shortcut to a reward. Jasmine's advice is right — withhold the reward for the fake version, keep attention flowing generously elsewhere, and it usually fades within a couple weeks once it stops working.

LMAOOO "genius con artist" is so accurate based on what you described. dogs really do be running little experiments on us 24/7 and we just don't notice most of the time

This is absolutely a real behavior and it's a great example of associative learning — Nacho linked limping to a positive outcome (attention, treats) during the actual injury, and now he's testing whether the behavior still produces the same result without the injury. Dogs are very capable of this kind of opportunistic association. The fix is straightforward: don't reward the limp unless you've actually checked for a real issue, and make sure he gets attention generously at other, non-limping times too so he's not starved for it otherwise.