hitAnimation: 26 is standard for bullets, vanilla as hell... But I can see the damageType: 3 entry under AUX_ROCK, which is explosive. So my guess is that the game is trying to draw an explosion but it's being overridden by hitanim 26 and therefore it loses its shit, technically speaking.
If I'm right, the solution would be either setting blastRadius to 0 or changing the hitAnimation number. Or changing damageType, of course.