If the voltage goes way too high then the BMS will disconnect the contactor and shut the whole system down. The system is totally geared around connected Victron products controlled by DVCC where the BMS through the Cerbo actively manages the charging in the devices themselves. However, what it is not good at is controlling chargers or loads that are not controlled by DVCC. In these cases you have to make sure that the settings on the individual chargers are correctly set and in addition wire them to the ATC / ATD relays if they have remote on/off inputs or add something like a Smart Battery Protect connected to the ATC/ ATD channels. What you really want to avoid is an uncontrolled charger or load from taking the SOC / voltage too high or too low and opening the contactor taking the whole system down.
I installed my NG system a few months ago and it is working well, all chargers are DVCC controlled, I added a Wakespeed WS500 controller onto the alternator to achieve this. Uncontrolled loads have a Smart Battery Protect so hopefully these are shut down before a total system shutdown. Well see how it goes.
The best news is that you have caught the high voltage pretty quick so you should be OK.