I think I had this guy's exact issue and maybe even stumbled upon his comment in that Microsoft support forum thread. It looks very familiar, but I could have just seen the meme before.

My problem was that I needed to do this for 100+ files, so using the UI individually for each file was out of the question. The eventual solution I found was in this tutorial for adding a context menu entry that changes folder/file ownership recursively. It's been very useful!