My LibreOffice window is stretched in a way that the edges of the window are not visible. The window behaves as it would if the corners were inside the window. This also applies to all pop-up windows.
Here is an image of the window of Writer, placed over another Writer window: https://drive.google.com/open?id=1uD-ORBQLwe1KaGZOhzOXgW-uWnKUWatw.
Note that my computer has a native resolution of 3840x2160, and a default zoom of 250%. I changed this to 100% and logged back in to secure the change and got this: https://drive.google.com/open?id=1qPreFdWYcniZVGvKO6wxLgiPioefsRPV. It’s a bit better, but the toolbar including File, Edit, etc. is still missing, and the bottom bar is still a bit cropped out.
If more details are necessary, I can try to provide them.
Update: Ratslinger’s comment to turn off OpenGL worked, and now the window is displaying properly. Thank you, Ratslinger!