GMT help

I made a Rootbeer on request, outside of the case everything worked perfectly, but when I put it in the case the GMT hand wouldn't hack any more, it does still turn as it should when changing the time.

I thought that the movement must be faulty or damaged so I took the hands, spacer washer and dial off and put them all on a new movement.

The new movement etc worked perfectly, wound, hacked , date change and time.

I then put in the case, SKX 007 , and again the new movement stopped hacking, everything else works.

Any idea on what I've done as it must be human error.

I wondered if I'd pushed it in too hard and it's pushed the dial too tight to the movement?