You can configure which display mode to use for which fps in the options under Video -> Display Settings. It'll map a specific display mode to any specific input fps, meaning you can configure one to use for 24 fps, one for 25, and one for 30.
You can also check which display mode a particular file will use by looking at its tags. Any video files have a FPS tag, which is used to deteremine the appropriate mode to use.
If a file behaves wrong, you can check these tags then. You can open the tag window by pressing Alt-Enter when having a file selected in standard view.