The floor can be 100% entirely correctly the same on both sides, but the tablet will behave as though they aren't, if you did not collect these.
never had this problem. i just left the treasurechests without collecting them.
Additionally hall 6: Its easier to just start from the beginning or the end and just move along changing everything as u move slowly to the other side instead of running wild across the room. It will be easier to spot changes to be made if u do it that way.