@JonnoH; from comments made in Victoria last year I suspect that contract tracers focus on what's most urgent and most do-able, in other words most of what was recorded as 'Under Investigation' is not followed up as attention turns to the most recent / most urgent cases.
NSW is now so far behind with contract tracing that a lot of its work will be focused on dealing with people in quarantine and isolation.
It's tragic for NSW that those irresponsible pub crawlers, engagement party clowns and the 'freedumb protesters' [mainly QAnon converts & Neo Nazis] spread the virus throughout Melbourne and have tied up its contract tracers.
