Clip automation corrupting audio

[AudioWeston]

Hi all

I have a major problem happening in Ableton that I have never had before, which used to work fine.

I am running a session in session view... triggering clips for my live show. Now I have some clips that I use just for automation which used to work fine. Now when I launch a clip that has automation on it Ableton maxes out on its processor power, stops briefly and then comes back with all digital distortion for a few seconds before returning back to normal.
Is there a setting or something I am missing? I have tried changing my buffer size but still no good.

Thanks
Steven

[AudioWeston]

Also... the midi indictor in the top right turns red when it happens