windows pdf highlight, underline, etc come with a square in mac preview? How to get rid of them in the first place? I mean, I don't want to delete them one by one as in the other threads. I just want to know how to prevent this happening at all(may be has something to do with windows), I am using foxit reader on windows. I also tried adobe dc reader

The squares are all empty, I didn't add anything in it.
This is a compatibility issue I think.
Same behavior happens when I copy something from MS Word 2013 to MS Word 365 (for Mac)
By the way, is it a macOS question or a Windows related question? If it's the latter, your question should not be here. :-)