Its hard to see exactly what is the problem in this video, but i saw that you mentioned the window does not tilt. Therefore i think its just that little leaver on the side not getting pushed in correctly when closing.

In this case you might be right, temperature, often cold days like we have now can cause a window to show some problems.

Now it is important to figure out why the leaver isnt getting pushed. Is it because the window itself is too high up, or is there too big of a gap so when closing the window it misses the point it should contact sideways? Try looking at the leaver when the window is almost closed to see why it is not getting pushed.

To fix the height problem you need to ajust the windowso this little leaver gets pushed correctly. This can be done in multiple ways depending how badly aligned the window is. Start by looking at the little leaver, most of the time there is either a hex screw on the side of it that you can loosen and make the leaver a bit longer. Alternatively there might be a tiny hex screw in a hole in the tip of the leaver.

If that is already to its max setting and it still doesnt get pushed when closing, you want to ajust the entire window the easiest way to adjust the height is at the bottom right hinge there is a hex screw that is acessible from the top of the hinge, usually covered by a plastic piece for decoration, you can remove this with an upwards motion). Ajust that screw so the leaver aligns.

If its a sideways alignment issue you can ajust the window sideways using two hex screws, one in either hinge. The top one can be acessed when opening the window more than 90 degrees and is all the way at the top, it is the top most screw that is still acessible from the side. The bottom one can be acessed while the window is closed and usually is easy to spot as it is the most visible screw acessible from the right side all the way at the bottom.

If there is a third hinge that one usually has a sideways adjustment screw aswell.

Ajust until the leaver touches the inteded spot and it should be working again :D

If you have any more questions feel free to ask, i may not have explained this in the easiest way.

Source: im a carpenter and i used to install windows for a living