Thanks @Ishan for the explanation. I did follow your steps but no luck.
Instead of going via import work-flow route, I manually inserted new
entry in nmsbroadlogmsg table with mailbox full error against soft
bounce event code, based on msgId, inserted similar kind of record in
nmsbroadlogrcp with other details like success / failure and deliveryID.
Now my expectation was in the background Adobe's job would insert the
related entries in nmsdeliverylogstats but that wasn't the case, as a
result UI...