After installing 6.5 on a new install of Oblivion, when i venture out and find a cave entrance the area I would expect to be a rock is a yellow block with a exclamation mark. I suspect is a missing graphic of some sort. It seems to be all the caves.
Oblivion is the GOG version. I installed OR then DarNified UI, Unofficial patch, Unofficial Shivering Isle patch, and Unofficial DLC patch. Everything seems to be working except for the cave entrance issue.