If there is a step between an explosion and a destructible line, the line won't take damage. I haven't looked at the code, but I'm guessing that damage is based on a LOS check between the pos of the explosion, and the bottom of the line's mid-texture. I've noticed weird things happen when damaging floors, too (in the demo for my destructible geometry handler
, firing at the grass with a rocket launcher only damages the 4 adjacent squares) so there may be a similar issue with that.
You do not have the required permissions to view the files attached to this post.