by DarkWynter
If I had to guess, I would say that you have a figure that just had a lot of glue in the torso at the factory. If you notice some figures come apart way more easialy than others, even if they are the same mold. If you look closely at the torso once it's open you can see where the glue was put in and it's not consistant. Some have a lot on the left, others just a drop around the pegs, ect.
The fix is pretty easy if thats the case. Just take an exacto knife and work down a seam, using the exacto method. You don't have cut it all open, one side should be enough to allow the figure to pop open after the procedure.
On a side note, with the customizing tool method if you are precise when you pop the figures open you will start to get a feel for just how much pressure is needed. It's like driving a clutch, when you find that sweet spot it should be about the same for all the figures. If the figure is a tough walnut and won't pop without excessive pressure, usually I will just flip the figure around and try the other side. If this won't work (I've only had one myself) I just work one side carefully with the exacto method, but you need to do this carefully to avoid making the seam look tampered with.
If you are finding bite marks in the figures when you pop them open, you may be either using to much force or a socket that is to big. I hope this was helpfull.