PlaySound suddenly intermittent

For some reason, occasionally sounds fail to play. This is a recent bug that has started happening, although it doesn’t seem related to anything I’ve done (code-wise).

If i stand and jump repeatedly on the spot, the character will play it’s jump sound the majority of the time (using PlaySound() from the pawn), then it will stop playing for a short period of time, then start again.

This is seeming to be affecting all sounds in the a game (they work most of the time, but sometimes not).

Has anyone experienced this before?

Actually, one thing I did do was check ‘Apply Ambient Volumes’ to the master sound class, so that my sounds are affected by entering a reverb volume. See previous post:
Help needed using ReverbVolumes! - UDK Programming and UnrealScript - Unreal Engine Forums!

Might this be bugged in the engine?

I’ve added some code that toggles bApplyAmbientVolumes on the master soundclass when the player enters/exits water (which does it’s job). For anyone who’s interested:

static function ToggleAmbienceVolOnSounds(bool bTrue)
    local AudioDevice _audioDevice;
    local SoundClass currentSoundClass;

    _audioDevice = class'Engine'.static.GetAudioDevice();

    if (_audioDevice != none) {
        currentSoundClass = _audioDevice.FindSoundClass('master');        
    if (currentSoundClass != none) {
        currentSoundClass.Properties.bApplyAmbientVolumes = bTrue;

However it seems like soundClasses are seriously bugged with regards to bApplyAmbientVolumes. When I’m in my reverb volume, I can play a sound over and over again, most times it respects the reverb volume and applies the low pass filter, then occasionally it completely ignores it (which totally breaks immersion in the game).

I’m really not sure how to resolve this issue. I wish I could simply apply the LPF to the AudioDevice itself.