Is there a profit limit on a single trade?

No. There is no per-trade profit cap at any stage, and no limit on how much a single position can make.

What does apply is the Consistency Rule, which looks at days rather than trades: it limits how much of your total profit can come from your single best day. A large trade is therefore never a problem in itself — it only matters if it makes that day large enough to push your best day past the cap.