The reason is that the wood gives way. All Outline elements are made with Scandinavian pine tree wood. As wood is a natural material, e.g., made of living material, it will work according to the season and therefore it may be necessary to adjust its elements during the course of the year.
In the autumn/winter, there is greater humidity, which means that the elements will ‘expand’. Therefore, the windows should be adjusted to achieve the right functionality despite temperature fluctuations and changes in humidity. Perhaps the strike plate needs to be loosened so that the window does not tighten or bind, thus achieving a better seal.
In the spring and summer, the elements will work the opposite way, because during this time there is not so much airiness as during the winter.
HOW TO SOLVE THE PROBLEM
Make sure that the side and top bottom frames are straight and level.
Make sure that the pedestrian frame has not jumped off of the rail at the bottom - if so, the door will continue to run, but will not close tightly. The moving frame can be lifted into place and the door will be closed again.
One can adjust the locking pin located in the frame on the impact side. It can be turned so that the door closes tightly.
Be sure to lubricate and maintain the brackets and hinges at least once per year.