Once the bees have been in a box for a while, they pretty much propolised/ brigde and burred combed everything in place.
If you're that worried, just make some wooden shim or buy some precut shims at HomeDepot/LOWES and push them down between the box walls and end frames and call it 'good to go!'
If you're that worried, just make some wooden shim or buy some precut shims at HomeDepot/LOWES and push them down between the box walls and end frames and call it 'good to go!'