I get this happen quite a bit as well. Like you say, exit and re-enter the game seems to help. Mrs F, I've tried all the usually tips and tricks, but, it seems to go away after a while and then rear it's head again a few weeks/months down the line. Frikken annoying, but, not a game changer. For me at least. I have ADD and OCD, so it freaks me the heck out, but, luckily, "rebooting" the game helps :-)