As for catering both doors before/while pax are disembarking 'when an a/c is running late'
Airtags not sure where you've gotten that from.
VB catering comes up the rear stairs (L2 door) when the pax have disembarked. If the scissor truck (R2 door) is used then it is done after the pax have disembarked and is all over before boarding has commenced.
Never have used or will use catering at both doors because it just ain't the way its done at
VB.
The Air China example is a pretty long bow as well.
Are all the
VB bashers in here just QF marketing people with nothing better to do?