Yes, there are definitely fence and enclosure glitches. In zoos where I don't have much money I make sunken exhibits with cheap fencing, and I actually saw a guest slide right off the path, through the fence, and down into the enclosure. (The exact reason you have to have fences for sunken exhibits in the first place, so guests don't fall in.) Also one time a crocodile somehow made it from the bottom of its sunken exhibit all the way up the ENORMOUS cliff I had separating it from the rest of the zoo. I've just learned to live with it.
The "zookeeper/worker can't get to..." or "educator can't get to podium" messages for me are the worst. In a big zoo they pop up literally every three or four seconds, as some worker will ALWAYS be temporarily blocked by a guest or animal. They really need to fix this so that if the problem persists for more than, say, 15 seconds, then and only then do you get a message. When I first started playing I would tear over to where the problem was, only to find the guest or animal had moved and the worker was now doing his job. I've learned to ignore them but they are still irritating.
(And the problem with ignoring is that sometimes there really is a problem. Either because of bad zoo design on my part or the fence glitch, I have had zookeepers get out of their enclosures where I often keep them, and then can't get in and start with the "zookeeper can't get to..." messages. Only when I went to the exhibit and found it full of poo and lacking in food or water did I realize what had happened.)
I guess it's just about your patience for the glitches. Mine is pretty high but probably not infinite.