The Auto Zoom feature when opening a new drawing is useful, no doubt about it (although I can imagine situations where it is not so handy).
But auto zoom every time you go back and forth between editing a block and the main drawing is... uhmm... utterly irritating (I wanted to say something else).
It makes it quite hard to keep your focus on the actual modifications you started out to do (and verify), thus creating an opportunity for errors to creep in (and an overall reduction in efficiency).
I might be missing a setting here, but IIRC QCAD2 didn't do that...
... just checked on ye olde laptop: it doesn't.
Is there any way to get the old behaviour back?