Layer from Copy malfunction, Photoshop 22.1.1

I thank you for taking the time to respond, Warren. It's true that if you have made no selection on a layer and hit Command J it will make a copy of the layer, but if you have selected any part of that image, Command J makes a layer of just that portion. At least this is what it usually does. In the case of the image I referred, I had made a selection with the lasso tool, but when I hit Command J to make a layer of just that selection, the whole layer duplicated itself. I tried many times, with different selctions, some made with lasso tool, some with magic wand and marque. Same result. This is not how it is supposed to work. Oddly enough, I later pulled in another image and it worked just as it is supposed to.

I had been working with a tiff file, so I went back the image I had been working on, collapsed all my layers and converted it to a jpeg and then I could select and use Command J to make a layer of the selection. So it had something to do with that one particular tiff file, but I don't know what.