The door to glass sealing gasket can occasionally walk along the back of the door. This happens due to the screws not quite holding enough tension on the door glass and so during the expansion and contraction process the gasket gets moved along a fraction each time.
This can be realigned by loosening the screws off and shifting it back into position so long as it’s not to stretched out. If it is damaged or stretched then it is easier to buy a new one and start again making sure to check the screw tension after a few weeks to adjust them back up to tension again. This gasket can be purchased from our Online Shop.