Battery discharges while charge controller is running, but idle is displayed

Hello, I have a problem with my Victron system.
I have a Multiplus 3000 (48V), an MPPT charge controller, a Hoymiles on the AC-OUT and a Hoymiles on the AC-IN (both integrated in VenusOS). In addition, a DIY battery with a JK-BMS (also integrated in VenusOS).
The following phenomenon keeps occurring. When the MPPT charge controller is producing, the battery jumps to idle. However, this cannot be correct because the PV power is not sufficient and there is no grid reference. Later in the day, I often have a real jump in SOC and voltage.
In addition, the total consumption is no longer correct. For example, my wallbox alone charges single-phase with 2kw, but the total consumption is only 1.8kw. My impression is that the total consumption then simply always corresponds to the sum of the PV power, i.e. the difference that it should actually draw from the battery.
When I switch off the charge controller, everything suddenly works normally. Even in the evening, when the charge controller only has a little power left, the system runs smoothly.
But how can the charge controller ensure that the total consumption is incorrect and the battery is discharged without the BMS noticing?

Does anyone have any ideas?

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