We tried also to put the big verbs on dispB and simultaneously modulations effects on dispA :

that changed nothing ,just the same results.You could hear the mods effects on dispA and the dry signal with the  2 big verbs on dispB; for a unknown reason, a "normal" verb , like majestic plate could be normally heared

As for the bangs,we had a big one 3 days ago,as the Amp was on standby :that does imply no inputs ,I suppose?

Otherwise,we saw the bang while recording on cubase: it is traducted by a short parallel double line on the screen