Ev charger rccb fault

[MrGwythers]

Hello can anyone shed some light on this fault, we have a supply into 63A 100ma rccbs that feed matte for ev chargers.
The rccbs keep losing a phase the first one lost L1 on rccb outgoing side, we've replaced that one now another 3 out of 5 rccb have lost L2 on all 3 faulty rccbs the first rccb has been sent back to manufacture, they've said both rccb and matte are compatible. But we can't work out why they keep losing a phase??

 

[MJPD29]

Sounds like they aren’t up to the task, although from the cable sizing id guess these are pretty small chargers. What size are they?

 

[MrGwythers]

Sounds like they aren’t up to the task, although from the cable sizing id guess these are pretty small chargers. What size are they?

They are only 22kw thanks.
We have a feeling the matte is causing some sort of problem upstream at the rccb and causing them to be faulty, manufacturer says they are compatible. Rccb has gone back for testing they will just say its been fried by whatever its feeding.