EA8150 - water distributor runs after

Greetings,
after a complete seal overhaul I have the problem that the machine runs the water manifold, either immediately after switching on (ie before heating) or after making coffee. It used to do that in between. Meanwhile, it's after almost every cup of coffee. If I didn't know better, I would think the waterworks doesn't know its position and is calibrating. Or somewhere there is still too much pressure in the system, but where and why?
Coffee water in the pomace is 4cl when turned on and rinsed, and 2cl after a cup of coffee. So everything is fine.
Crema and pressure balance in the cylinder are super, because up inside everything looks nice and clean, except for a bissschen coffee dust, from grinding.
Drainage I have checked several times. Seal is new and operated with and without silicone grease. Changes nothing to the pre- or post-run of the waterworks.
If the microswitches on the WV were defective, I'm sure the machine would no longer work.
Do you have any other ideas why the water distributor is running down? And no, I haven't opened it yet, because according to the forum, there are only ceramic gears in it and it is normally maintenance-free. It doesn't make sense to me to open it, because it obviously works very well, except for the overrun.
Thanks in advance for any constructive ideas.

And please no comments that the machine is crap, etc.
The maintenance may not be easy, but is doable and fun ;)
PS: Coffee is hot and extremely tasty with the right coffee :)

Short basic history of the machine: .... after over 4 years of trouble-free operation, the piston seals were gone and as you know, a complete revision of all seals was necessary


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Unfortunately, there are some seals with poor quality, so that I had to replace some of them after 5 years.
The most interesting of these was the last one, namely the crema valve. The old one was completely hardened and let the pressure through/blown off much too late. Had the consequence that the cleaning with the tabs worked poorly and the pressure was not completely released after preparation, because the pressure in the chamber was quite simply too high and thus the time was too short. Exchange was of course only possible with a complete piston. The CV gibts not individually :(
The hydraulic cylinder is also completely revised because water penetrated and let the upper spring ring waggammeln.Gar not so easy to get a new ring at a reasonable price.