Priest of the Sun fire beam goes through walls on Savannah map

The title says it all. Since Priest of the Sun's fire beam tracks you with significant range, one of the only ways to play against it is to use walls/terrain. I tried to use the walls on the Savannah map for protection, but the fire beam went straight through them. This happened to me twice in one map, killing me both times.

lol damn that fucking sucks - wish you had video of this

The few maps I've seen these enemies they've shot straight through everything.