Thanks for the response, macropod.

I've checked that the drivers are the latest and Windows is up to date. (unless there is something I don't understand about how to do this.)

Now it is acting up on my machine. I'm working on a Windows 10 64-bit SurfacePro 7 with an LG 34" WQHD widescreen attached via HDMI cable. I created the workbook with the LG screen as the working screen and the SurfacePro screen off. If I used extended displays or turn off the LG and turn on the SurfacePro screen only, the same issue occurs.

I've read online (vba - Excel: the Incredible Shrinking and Expanding Controls - Stack Overflow) where others have this issue and have solved it by setting the control height and width on worksheet activation using shp.height = shp.height and shp.width = shp.width, and it seems to "undistort" the option buttons, but for some reason, it also moves them to a different location. It completely resizes buttons and dropdowns as well as moves them. It also moves checkboxes.

Does the additional info give you any other ideas?