For a long time I've successfully been using the JQL search below to find certain Jira issues with missing labels.
project = XXX and issuetype = bug and status not in (rejected,resolved) and (labels not in (TS1,TS2,TS3,TS4,TS5,UAT,REG,OPM) or labels is empty)
Recently, the search stopped working as before and now the result list contains Jira issues with labels that are to be excluded.
After tinkering a bit with the JQL search it seems I get the same result as before if I split the search into two separate searches like this:
project = XXX and issuetype = bug and status not in (rejected,resolved) and labels not in (TS1,TS2,TS3,TS4,TS5,UAT,REG,OPM)
project = XXX and issuetype = bug and status not in (rejected,resolved) and labels is empty
This makes me suspect there's something wrong with the interpretation of the labels is empty statement.
Did Atlassian make changes to the way JQL searches work lately?