When leaving a factory building, you will be sent to the last place the building was built at, even if the building has been picked up by now. This is for multiplayer reasons. You might just have the building left in storage or your inventory somewhere. If you destroy the factory building's exterior or the item, the interior will also stay there in case you want to get it back using console commands.
Note also that Factory Floor 54 may be home to several factory building interiors depending on your settings (by default your 54th, 154th, 254th... factory buildings). Check the map inside that factory building to see if there are other factory interiors on that floor. Factory floors are offset by 512 tiles on any given surface.
If you see any roboports in any factory building on floor 54, just add some storage space to that network to fix the issue. If there are no roboports, just place one down to lure the bots in, even if they are trapped in the void.