Track changes spontaneously switches colors

This is driving me bananas because I'm tired of constantly turning Track Changes on and off. While I'm editing, if I go back and try to delete something I've just typed, it treats it like a change from a different author and does a strikethrough instead of an actual delete. Track Changes also spontaneously changes color every so often while I'm typing, again acting like I'm a different author. So in one paragraph, I can have both green and blue text -- if I try to delete blue text, for example, I never know whether it will actually delete it or whether it will turn green and strike through instead.

What can I do to stop this? I have Word for Mac. Thanks!

ETA: I also noticed that sometimes a sentence that starts as blue turns green after I hit Enter. This is driving me nuts!

I haven't accepted the changes because I need to keep them visible for my editor. I did some searching on this problem and all I found is "that version of Word is buggy."

ETA: OK, it seems to have settled down for now. Grrrrr.