EDIT: removed the image link from 1), might have been misleading.

This is not going to be very helpful, I'm afraid. Three bugs in one post.

1) Sometimes the whole screen will not render within one frame, leaving part of the screen completely black. The parts rendered and not rendered are not divided in a straight line, but rather indicate rendering column by column, then big square by big square vertically (big squares being about the size of 2 by 2 tiles). I'm not sure if that's exactly how it looks like since it doesn't happen often and it only lasts for a split second. It's not an in-game field of vision bug as not even the user interface is generated. Never happened to me in the menus or inventory, only while walking around dungeons. No known steps to reproduce. Happened before and after graphics driver update, in R59 too.

2) Karmic dragon sprite was missing, tile mode. Health bar was present, but the dragon's sprite. Curiously enough it was able to reappear and disappear randomly every several seconds. Happened in full screen mode. Stopped happening after I briefly switched to windowed mode. It occurred with two different karmic dragons, although within one game run-time. Happened in R60.

3) Similar to above, I've had one frame of red water in Tomb of the High Kings not appearing, instead rendering nothing (i.e. black squares) in that frame. I don't remember how it behaved in windowed mode and after switching back to full screen. Happened in R59, only once.

As usual, OS was Windows 8.1 64 bit.