Im working on win10 and i copied a document to another file. Then i tried to work on the copied version, but i changed the original file instead. It lists the right path of the file on the top. I nearly freaked out cause i thought i had deleted precious writings, but ofcourse they were still there in the copied file.
That is a hard bug and i can't rely on that dark magic!!!
This sounds like a serious thing.
Please describe exactly what you've been doing, so that I can reproduce it.