E92 N57 325D starting problem

[PATO Z]

Hi. I have an E92, engine n57 325d. Sometimes there is a problem with starting. I have already replaced the crank sensor, cam sensor, sensor and fuel pressure regulator on the ramp and the pressure regulator on the high-pressure pump and I also replaced the low-pressure pump. The problem is still the same, I have had the car for 2 years and it does not improve or worsen. When starting and about every fifteenth to twentieth time after pressing the start button, the car does not start. The starter turns but the car does not start. I can press the start button several times but the car does not start.
But when I take the key out of the slot and insert it again, the car starts immediately.
I am wondering if there is a problem with the CAS module. When starting it feels like diesel is not getting to the injectors.
No errors in the fault memory.
I am an electrician.
I cannot get to the wiring diagram to measure anything sensible.
I don't know what the CAS module disconnects?
Does the CAS module also disconnect the injectors?

[aade]

I'm not terribly good with diesels, but this sort of sounds like glow plugs. Could be some sort of relay fault. Diesels tend to fire up when there's enough heat along with the pressure. Glow plugs are supposed to make the heat portion happen quickly so that the pressure will cause ignition. If the relay doesn't send power to the rail with the glow plugs (supposed to happen when key is inserted) and it does the second time around, it sure sounds like electrical. One theory is that if the car doesn't start from deep sleep, that there might be a power delivery issue to or from the relay.

Question: Does this happen once the engine is up to operating temp, followed by a restart?

To me this is not an immobilizer issue.