I am logged in as admin and everything is normal. Matter of fact, I came to the SP site today to look for any new plugins... saw the tinyMCE and downloaded it. I uploaded it and got an error, because it was already uploaded.
I suppose it's been non-working for years. I think I will delete and reinstall and see it that does some good.
I would not have expected the update to make a difference. I am also out of ideas as to what the cause might be - not something I've seen before or that anyone else has reported in the past (as far as I can tell). I think this is one of those cases where you might need someone to get on to your site to see what else is going on.