On Windows 10, with a 4K screen (plugged via DisplayPort) configured to use a scale of 150%, when locking the screen (and the screen goes into power saving mode), the Chrome windows resize themselves.

I notice this because I use divvy to arrange my windows neatly. I noticed that other application windows are resized if their size/location is not on pixels multiple of 3, so my guess is that when screen goes to power saving mode, windows internally resize the display to use scaling 100% instead of 150%, then reapply the scaling when the screen is powered again. If location is multiple of 3, then the round-trip does not introduce any error (3px -> 2px -> 3px).

For Chrome however, even if the pixel location is a multiple of 3, the windows resize themselves, losing a few pixels each time (it is easy to notice because I use divvy to have Visual Studio and Chrome take the same location on screen and after a few locking, the Visual Studio window border becomes visible when Chrome window is selected).