Although turning off each and every one of the new "Tiling" functions in system preferences diminishes the effect - it does NOT remove it altogether. There is SOMETHING, some elusive "gesture" that normal Mac users do dragging windows here and there - that still causes the window to "maximize" (not to "Full screen" mode - just take the whole size of your current screen), which drives me nuts.
Old Mac users like myself (since 1987) are pretty strict with where their windows should be and what size they are. I find myself cursing again and again, trying in vain to maintain my "work bench" so I can see things I need together, drag things from one window to another quickly etc.
This is - again - Apple crumbling down on us. The Mac really "gets in your way" nowadays. Zillion authentications, Zillion "no, you can't do that", Lots of functionality REMOVED from apple Apps, in favor of more and more cluttered eye-candy visual effects that help NOTHING with your work and fun.
Even the "Focus" feature (presumably made to help user stay in Focus) takes all your focus for itself!!! what huge configuration strain and things just "happen" all the time while you're trying to work.
This issue with Windows is just the last straw.
It's time some decent engineers left Apple to write a new operating system-- for the rest of us.