I have a stack of 4 APS and the one on the bottom (a T10) acrylic sliding doors are bowing out. I can hardly open and close them anymore without scraping them up or they pop off the track. Im kind of ticked as the oldest cage is only a year old. I moved that cage to the top of the stack to see if that would help and it hasnt straightened out yet.I put the two with glass on the bottom of the stack.

Its bad enough that they forgot the holes to stack them in one and in another they didnt give me any of those stick on handle things(not sure what they are called). All these little problems are starting to add up.