Just to update, I have not been able to notice any difference in level between the two sides since have started testing at home. I have not tried different cables yet to see if using non matching cables makes a difference or if I have a problem cable.
As a result of just playing around, I found the balance control on the actual Qu Pac itself, so there is one good thing. It’s not as obvious as it is on the iPad. Either way it was set to the centre position so that wasn’t the problem.
I think the cables are as good a candidate for causing the issue as v 1.9 maybe even better. The only way to really know will be if it happens again and I can swap the cables at that moment without powering down the Qu Pac. I’ll do some testing with various cables in the meantime.