Generative AI remove tool leaves a shadow behind

This is a frequently asked question. Most likely you have an AI mask, like a sky mask (or the invisible mask of the Adaptive Profile). That mask was created when the object you now removed was still present, so that mask has a gap where that object used to be. That’s what you see. The mask needs to be updated and Lightroom is actually telling you that by showing a yellow ‘wheel’ in the upper right corner of the right panel. Click on it.