We have seen what we are pretty sure are last years offspring return to the same nest they were born in with there parents prior to their parents nesting - but this is pretty unusual - not sure if this is because we usually miss the return and last years young are shooed on (which we have observed) or whether there is a high loss rate of post fledglings chicks or whether the time at which chicks leave their parents varies.
Yes, they remained on the nest hollow perch for a bit, then moved on to other nearby trees exploring hollows and chewing bark. There was at least one other pair doing the same and they were all talking to one another. Would you expect the offspring from last season to return to their birth place?