I can't find a platform-agnostic search, so starting here:
change a filter dropdown, e.g. change "Minimum Score" from 9 to 8, then ensure that "Platform" is still set to GameCube. Click "Refresh List". Note that the titles in the result list on the left are not restricted to the selected platform.
Please fix your search function.
(Same results from this page: http://hiddenfallsgolfclub.com/pc/games/)
Chrome on Windows 10 64bit.