If you rename a object and remove the # at the beginning, if you try to use it in a trigger it will error.
There are 2 ways I see that this could be fixed:
1. You cannot remove the # (if you try, the editor will just add it back)
2. The trigger stops erroring if you don't have the #
Had a headache for a solid 12 minutes why a trigger keeps having errors with some objects just to find out that it's because I didn't keep the # at the beginning.