Audio playback drop out but click continues

Cubase 8.5pro on a Windows 10 PC. I’ve searched but nothing seems to hit all the bullet points of the issue so apologies if I have missed a relevant post. The issue is that when recording a new audio track (guitar), the pre-recorded audio track I’m playing along to (drums) keeps dropping out. The guitar recording continues as does the click. Pretty annoying when your trying to vibe :angry: :laughing:

The drums are mixed down from 12 channels to a single stereo channel. The fact I’ve mixed 12 channels with plugins to get to here should indicate that this PC should cope. I’ve looked into buffer sizing and driver updates etc… Any ideas on what else I could try?

Thanks in advance!