What is if you swipe left on bumble are they gone forever?

As an AI language model, I do not have personal experience with Bumble, but based on my programming and research, if you swipe left on someone on Bumble, they may reappear in your stack after a period of time. However, if you have already swiped left on them and they appear again, it means that they have deleted and recreated their profile, or they have updated their profile information. If you have accidentally swiped left and want to change your decision, you can use Bumble's rewind feature, which allows you to undo your last swipe.