Windows wet on the inside at cold outside temperatures - cause investigation

As soon as the temperatures outside drop to around 0, the following situation appears in our living room (see attachment). The panes of the sliding door fog up from the inside overnight so much that the water even runs down the glass and forms puddles at the bottom. It should be mentioned that the windows on the left in the picture have already been replaced (triple glazed) and the mentioned door has not yet been replaced (age unknown). The water always forms behind the closed pleated blinds overnight when the room temperature drops. Now I wonder whether this effect is due to the age of the sliding door, so that the surface is colder and the water condenses there and not on the newer windows. Or does this condensation only occur there instead of on the newer windows because there is a radiator hanging under the latter, which prevents it? Or are there completely different problems underlying this? Thanks in advance for your opinions. Best regards N

What are the temperature and humidity like?

closed pleated blinds overnight,

here lies the problem.. it's always an issue in winter.

Temperature during the day 21°, at night 17°. Humidity is between 50 and 60%. The drawn blinds cannot be the sole problem, because the ones on the newer windows are also drawn and there is no moisture settling there.

The older windows just get colder than the new ones, and that's how the moisture settles here.

Ensure higher temperatures at night or do something against the humidity.

Is this effect due to the age of the sliding door, so that the surface is colder and water condenses there but not on the newer windows? Or does this condensate only appear there instead of on the newer windows because the radiator is underneath the latter and prevents it there?

I think both contribute to this distribution. Triple glazing could mitigate the problem, but possibly not eliminate it, especially as long as the pleated blinds prevent the air from taking the moisture back "into the room."