So, the way the audio works in this game is that the audio system can only play a limited number of sounds at once (around 40, iirc). These sounds go into a buffer to be played by the CPU. Each sound is assigned a priority so that if the buffer is full, a higher priority sound will kick a lower one out of the buffer so the player will hear it. So the game will “clip” lower priority sounds in favor of higher ones. Dogs and trappers have high priority, so you will almost always hear those. It seems that the overhead attack cues for Crushers and Maulers have their priority set too low, such that sometimes the audio will not play.
This could be easily fixed by increasing the priority of those sound events.