the 'crash' sound effect when striking a target is sometimes soft, sometimes loud

[Mike-B-22]

What controls the volume of the "crash" sound effect, when you hit a target in Punch Mode? I notice that 80-90% of time, I'll hear a nice loud thundering crash sound, as expected, but then sometimes (at least every few seconds) there will only be a soft "plop" sound, even when I smash the target dead-center with all my might. Is this a bug, or has anyone else ever noticed this before? I'm playing Moon Rider with the Meta Quest 2 headset, just discovered it yesterday and already I'm in love with the game. I just wish the target-strike sound effect would consistantly be a good hard LOUD CRASH like 100% of the time.