>>1797425>>1797479Sometimes the tip of the canti stud gets mushroomed just a little (over tightening the pivot bolt). I've never seen the bushing get stuck though.
If that was my fork, I would put it in a stand & use a 6" or 8" smooth flat file to go through the wall of the bushing. It's a controlled movement (vs using a set of vise grips, or dremel w/ baby cut off wheel), and even if you 'break through' the brass, you're not going to gouge or deform the stud.
I looked at that Stack Exchange answer, and a bearing knife & puller is a good idea, but I've never seen them that small.