sql identity column generate always (WHY HAVE TO RESET)

id BIGINT NOT NULL GENERATED ALWAYS AS IDENTITY
(START WITH 1 INCREMENT BY 1)
primary key(id)

We all know that sometimes the identity column gets "out of whack" and that
we have to reset it with the alter/restart...

My question is why does it get out of whack.
Even better question, how can we detect the presence of the out of
whackness before we are faced with a "attempt to write duplicate" because
it was "out of whack"?
Is there a system table we can query to look at to detect these time bombs?

Abused google looking for an answer and everyone prides themselves with how
to restart it... and never is it explained how to detect them beforehand.

TIA

jay