Audio cut out trouble

[GuitarKit]

Hi folks.
I'm working on Cubase Elements 9.
I'm doing an ambient track at the moment that is quite pad heavy. As I worked on a particular section the audio just cut out all of a sudden. It always happens in exactly the same place.
I thought maybe my CPU is having a spaz so I deleted all but one audio track but it still happened in exactly the same place. So, can't be CPU?
I've checked for any unwanted volume automation dropouts. I've only got two reverbs going with sends to them.

Any ideas what else the audio drop out could be?

[lesmac]

Maybe mute automation? Check the master track as well.

[GuitarKit]

Well, I ended up importing the stems into another session. It meant I had to rerecord the audio because the dud session refused to bounce.
At least I recovered.