I agree, the RR seems to be the culprit, I just plotted the data in Excel and see this:
View attachment 22883
I definitely think that the RR is pulling down the RF and the LR, here are the height changes vs time:
View attachment 22884
It looks like after three hours the rear is already dropping but only by 1/8".
Checking that the RR pipe and connection to the valve is going to be interesting, so things it could be:
- Pipe fitting to airspring (o'ring?)
- Pipe to rear valve (o'ring?)
- Leak internal to the rear valve (so venting to the gallery), does the gallery pressure rise overnight)
Keep us posted and good luck with the weather and not freezing!