I would say this has to do in some way with a tail dropping. Now keep in mind I AM NOT A VET IN ANY WAY SHAPE OR FORM. From what you describe I can only imagine that it could be a botched tail dropping. My explination is during their everyday living at some point the tail got caught on something or under it and before the tail dropped the anole got out. What could happen is the tail has dropped (thinking it was caught) but is still "Attached" (the skin did not let go) The problem is the tail is dying. This is all based on a complete guess without having seen the problem I can only guess that this has happend.
Take it to a vet asap. If what I have said is true the the tail can get infected and all sorts of nasty things can occur because of that. Good luck
Shaon94