Sometimes when trying to use the spot Removal tool while zoomed in on a spot, the tool will seek for another spot to take from that is far outside of the zoomed-in area which results in me being unable to pull it back in to a better spot. I should be able to move the photo around while it's zoomed in, but that isn't possible, so I have to un-zoom and undo the spot removal to try again.
If you move up to the latest version, the Spot Removal Tool has been drastically improved - now it works like the similar tool in Photoshop, not trying to just copy a region. It is really quite an improvement. With this change, there is no longer a button or a display of the area from which things are taken; it just fixes the problem quite well, most of the time. With this change, it doesn't show anything except the area being fixed, so the problem you experienced has disappeared!
Richard: I don't think your statement "there is no longer a button or a display of the area from which things are taken" is correct, The spot removal tool seems to work just as it always has. Perhaps they have improved the algorithm which is used to select a source location or do a better job blending the copied pixels into their new location when using the "healing" mode, but I still get both both the source and destination locations circled and both are still movable.
Richard, Dan is correct. You are obviously not referring to Lightroom Classic 8.3 for which nothing has changed in the spot removal tool. It is still reasonable at removing small spots, but poor at removing larger objects and often selects a source area outside the visible area for a cropped image, especially near the edge of the crop boundary (reported long ago and nothing ever done to fix it).