A client of ours has an unreliable VRV 2 System. They have had multiple refrigerant leaks on the Electronic valves within the fan coils. We have been to site and replaced 3 on separate occasions. On each occasion we have had to replace 40kg of lost R401a, so as you can imagine after replacement part, pressure testing, evacuating the system and recommissioning it turns into expensive repairs.
The client is always upset that this has keeps happening, and as the company that looks after this equipment its feels embarrassing to have to explain yet another part has failed. This has happened with about the frequency of every 6 months. They have also had 2 inverter compressors replaced and another leak on the condenser coil.

In one year they spent £9000.00 in repairs, and on one system thats too high.

This is an install we have inherited, and have taken over the maintenance for the last few years. it was an untidy install with lack of brackets holding up pipework, uncut cable ties missing flare nut covers. These minor things are repaired during servicing, but wont be a cause of the issues.

Being a contractor that wants to offer a solution to reducing costs for them I am asking you guys. I have some feelings why it is the way it is, but I don't know everything, and with the collective knowledge of the forum maybe someone has a solution.
I have been in the industry for 20+ years ands its the most unreliable system I have come across.

How can we reduce the likely hood of these electronic valves from failing in the future?
Why this is happening?
Anyone know if this is a common problem?