Audio channel not playing back audio

I noticed this in a few projects in 7.5 but it has popped up again when a client stated a few elements where missing.

Upon going back and checking the channel, the audio channel will not playback audio (others play fine)

checked all things like routing, mute etc everything is fine but for some reason its not playing back

It has some heavy duty realtime plugs such as rx declick so there is a pre load not sure if its that, anyone else have this issue?

fixed it, something to do with ohm boyz delay.