BUG #16240: The now() function is populating different date time than expected

PG Bug reporting form <noreply@postgresql.org> writes:

We have certain columns in our database of data type 'timestamp with time
zone'. We are populating them with now() function as default value
.Sometimes the date time is getting populated as dates from 2017/18
randomly. What can be the possible cause of this issue?

The most likely bet is that something is issuing insert commands with
non-default values in that column. now() itself does basically nothing
except read the transaction start timestamp. If you were seeing lots
of *other* weird time effects, like say timestamps in the postmaster
log jumping all over the place, maybe it'd be possible to believe that
there's something wrong with your server's system clock. But I'd
start by looking more closely at your application's SQL logic.

regards, tom lane