I have the same issue as well— 2 of mine came off, and I just stuck them back where they were before and let the pressure of the heat sink hold it in place for now. But any expertise on this issue is appreciated!

I don’t have much to add other than that these squares on the GPU and CPU were hindering my ability to completely clean off the previous thermal paste. I actually would like to remove the squares, but would like to hear from folks who might have a sense of how essential it is for thermal transfer (or any other purpose it serves).