You can filter out concerns by status (ie. linked with TICKET_STATUS AV).

But if you use this "Filter" link on top of the page to remove the concerns with this specific status, it will also remove the concerns without a specific status.

concern 1 | Open
concern 2 | Resolved
concern 3 | status_1
concern 4 | status_2

"Filter status_1" should remove concern 3 only. However it will only show concern 4.

This is because the query is ([-and => {status => { '!=' => "status_1" }}])

And does not include status that are NULL in DB.

use Koha::Tickets;
my $t = Koha::Tickets->search;
say $_->status // "undefined" for $t->as_list;
say "===";
$t = Koha::Tickets->search([-and => {status => { '!=' => "status_1" }}]);
say $_->status for $t->as_list;

undefined
undefined
status_1
status_2
===
status_2