Not strange at all - the APC (Auto Power Cut off) magnets located just before the neutral section will trigger opening of any VCB whether the pan is up or not.
That's not necessarily the case. On old-skool BR era electric stock that would happen, because the APC control was specific/local to the vehicle that has the VCB/pan on (provided aux set and battery fuses not out etc) but it isn't necessarily the case on modern stock, because the VCB control isn't necessarily 'local' to each vehicle, but instead is often syncronised/managed through the TMS. This means it's entirely possible that only VCB's that have the pans up, get opened/closed.
There's at least one manufacturer out there where the multiple VCB's on the train are all controlled via the TMS, based on commands from the leading VCB fitted vehicle, regardless of what the APC receivers on the VCB fitted vehicles further back, pick up. It means you could have the ridiculous scenario where the leading vehicle opens the VCBs, but due to a fault in the APC receiver on that leading VCB fitted vehicle, it doesn't reclose the VCB on that vehicle and therefore none of the following VCB's re-close either (even though the APC receivers further back on the train are working fine). Progress, eh?
Whole heartedly agree that the modern single-pot Alstom VCB's on most modern EMU's are *shockingly* noisy when they operate. Really alarming to passengers. Absolutely nuts that's where we've ended up.