How does this happen? 😦

Edges need a gap for expansion.

When you were too cheap to go with the concrete foundation so you used jello.

That floor should have no less than 1/4'' from the wall or they expand and contract throughout the year. It should have also been glued to the floor at various points. Home owner install.

It’s called a floating floor for a reason. 😜 If this is happening and it’s not water you need to trim the edges a bit.

Climate change or free Gaza or something rainbow

Didn’t leave a gap along the wall is the first problem

The put the floor in right against all the walls at some time that wasn’t during the heat of summer. Then summer hit. No room to expand.

I'm going with, "there was alcohol involved" during installation.

Not enough expansion. Also it’s a plastic floor so it was never going to last in the first place.

It is free floating laminate "hardwood" and you are not supposed to do runs greater than 30 feet without a seam or it will buckle like this. Leaving gaps at the wall would have help but large areas need expansion joints.