Rear stove panel loose

The very back wall of my yotul F400 Castine is loose. I noticed it when I was moving some coals around removing ash. I bumped the rear with my shovel and heard a clang. Put some gloves on and the whole rear piece moves front and back. This can't be normal... does the stove cement hold this piece in place? Thx

Sorry here a picture of the panel from inside the stove...

I know it's not cemented, but I don't know if it's normal for it to be really loose - but if it moves just a bit that's fine. If you remove the baffle plate, the rear cast plate can be removed w/o tools - 3 firebricks behind it. I would just make sure the secondary baffle is resting in the right spot & all gasketing (underneath the baffle plate is in place