The bug seems to only occur when the Keyboard Mode is off. If the Keyboard Mode is on, the bug doesn't seem to occur. Here's how to reproduce the bug:
1) Stand next to a bunch of wall tiles (I did it in a cave level)
2) Using a melee weapon, destroy a wall tile at upper-left or upper-right (either with mouse or keyboard)
3) Move to that space using your Shift+arrow keys (don't use your mouse)
The result is that the whole screen shifts toward the right-side, away from Cogmind. If you continue to destroy a wall tile and move diagonally upper-left or upper-right in this way, the screen will continue to shift further and further away. This bug does not appear if you use other means of moving diagonally (number pad or the 'U'). It also does not appear if you destroy a wall tile diagonally bottom-left or bottom-right.