I've been troubleshooting an interesting issue with my EAS which is affecting the rear left corner of my P38 (now named Rachel).
It started yesterday when dropping to highway height caused a hard fault. I reset the fault, drove on and got to my destination. On the way home the same thing happened again after dropping to highway height. In both cases the fault was related to the left rear valve.

Fast forward to today. Did some troubleshooting and found the following. Actuating specific valves using the EAS Unlock software from Storey works on all valves except the rear left valve (consistent with the symptoms so far). I measured the current to the left rear valve's solenoid (little black wires into the solenoid body) and there is no current flow when actuating the valve. All the other valves read around 1,2A when being actuated.
Cool, makes sense so far. Checked all the wiring I can get to without removing the valveblock and it all seems fine, so my next step is to remove the valveblock and check the wiring that I can't get to with it installed.

First step is to depressurize the bags for valveblock removal. Here is the strange part: the rear left corner deflated down to the bumpstops! This means that the rear left valve must have been actuating correctly right? Or is there some different logic involved here that I am missing?

For completeness this valveblock and driver unit all came from a wreck that had been put on coils before being scrapped. I rebuilt it (o-rings, diaphragm etc) a week or two ago and it has been working properly until I had this issue yesterday.
I'm going to continue stripping the valveblock out and perhaps swap out the driver unit from the valveblock that I got in the car originally.

When you step the valves one step at a time from the Heights tab, do you hear the solenoid click? Two things can cause a circuit to go down, either a dead output from the driver pack or a dodgy connection in the plug between the driver pack and the valve block. If you've got a spare driver pack, swapping them over and giving the connector a good squirt of contact cleaner, should sort it out. Once you've done it a couple of times, you should be able to swap a valve block and driver pack in about 10 minutes.

When actuating the valves one at a time I do hear the solenoid clicking. I was struggling to differentiate between the inlet/exhaust valve clicking and the airbag valve being actuated, hence the use of the clamp meter to measure where the current is actually flowing. This pointed me conclusively to the LR valve not being actuated.

I've now got the valveblock on the bench and supplying power directly to the LR valve solenoid actuates it, and the current draw is the same as the other valves so I'm thinking the valve and it's solenoid are all good. The wiring also seems good, although I'll test that a bit more thoroughly before swapping over the driver pack.

More feedback soon :)

Are you testing directly to the solenoids or via the driver pack? Doing it via the driver pack is the best test as it tests both the solenoid and the pack.

I posted how to test here https://www.rangerovers.net/threads/clarification-on-testing-a-solenoid.342547/#post-2305928

On the bench I was testing directly to the solenoid, not via the driver pack, so I was probably putting way too much power through them. but only for an instant so I'm sure they would have handle'd the abuse.

Anyway, all is back together now and the EAS is working as it should again. So the issue here was definitely the driver pack!

Another discrepancy between the old an new driver pack is that the old driver pack was putting about 100mA trough all the solenoid coils constantly, whether it was actuating them or not. The working driver pack doesn't do this.