ᐅ Does a screed floor expand or contract significantly?

Hello everyone, I bought an apartment. The landscaping dates back to the 1970s. I have the feeling that the screed is shifting. Is it possible for that to happen within, say, one hour? I know that screed can expand, but not within such a short time, right? I have a vinyl design flooring with a click system. It cost 25 euros per square meter (about 2.30 USD per square foot). I installed everything correctly, with expansion joints everywhere, and I let the material acclimate for several days before installation. Now, several times a day, suddenly the floor becomes uneven and develops something like bulges. Does anyone have an explanation?

What does one have to do with the other in your question?

Maybe the joint is too narrow at one corner? I often see that the gap on the walls is sufficient, but at the door frame it has been fitted tightly.

That is definitely not normal. My hardwood floor was fully glued down and is perfectly flat.