I was playing a game with some AI, when I encountered this bug, the keyboard itself and some of the mouse would still work, but not well. I would be able to left click to select units or scroll around the map by left clicking on that map, but otherwise I couldn't move the camera, the keyboard wasn't functioning at all, except the enter key for some reason, and alt tabbing, so the keyboard itself was working but no other key other than entering a message? I was also able to pan the camera by using the middle mouse click, and command my forces and won the game, since there wasn't much left at the moment anyways.
This issue occured after switching from dragon mode, to overview, the only reason at the time I could imagine this occuring was because I either did it really close to a cliff, but not that close either, and the camera or something thought I was in a cliff (Even after panning away from it, not clipping the cliff even) or because I did this and kept moving around? I know at one point in the game I was still moving after I hit R, but I don't remember if it was the last time, or before then, and earlier in the same game. It wouldn't even let me switch back into dragon mode, hitting the menu button from the UI at the top I was able to get into options but I didn't change anything other than tutorial mode, and I didn't see anything else being an issue anyways. A hidden bug I would assume, but a critical one it seems.