In several levels of the Prototype DLC, mines will target and kill me even thru walls. I've found only a couple other reports of this bug on steam, both of which just say 'Restart Checkpoint in the menu will fix it" but I've tried restarting, holding x, and several graphics options with no change. It makes some levels completely unbeatable, so any suggestions would be greatly appreciated.

I can confirm this. Actually "restarting the checkpoint" worked for me in PuzzleSet 01. But in PuzzleSet 02 mines are still exploding through the walls therefore DLC cannot be finished.