Very strange behavior. This happened to me from times to times. Right now, it was same but at almost the end of upload (="uploading" vs "Waiting to upload"). I tried to cancel the copy but could not. No effect on the cross. I went to Force quit to close the finder from there : Finder icon had wrong icon, from another app. I closed that app. File copy finished without doing further command. Just like if there were some process mix. The files I tried to copy were not related to that app.