I don't know if I am misunderstanding this or it's a bug.

I have on a bunch of occasions had specialists that I cannot get rid of. What does (1 Forced) mean for a specialist? Sometimes I have like 5 specialists that I cannot set to working food. I do have extra health and happiness so that's not the issue.

There are a few wonders that give "free" specialists, that could have something to do with it. Though it does seem the specialist assignment is a bit quirky.

I beleive one forced means he has to be a specialist because there are no tiles that can be worked left (most likely due to culture or being used by another overlapping city).

Did you get any GP's you turned into super-specialists? They can't be undone.

But yeah, some wonders do force certain specialists.

I remember when I specifically clicked the + icon to assign a specialist, it said "1 Forced" when I mouseovered it. I also had the governor on, so it might be telling me that I assigned it and that the governor didn't.

If you can't "-" them, it's probably free from something. I'm not exactly sure what "free" means, though.

Certain Civics and Wonders give free specialists. These can only be used as specialists and can not be assigned to work the fields.

I have had times that I cannot remove specialists if the City citizen manager is on (the one who controls which tiles are worked). It seems to only allow you to switch to other specialists unless you turn off the manager. If you turn off the manager (one of the buttons just to the left of the minimap in the City view screen), you should be able to remove the specialists (unless they're free, as the above people mentioned).

I had a size 11 city which was only working 7 tiles + city tile. On top of that I had 4 specialists and I couldn't get of any of them. Are you saying that these are due to wonders?

possible, or possibly the other tiles were being worked by other cites and/or had hostile units on them