I've got reply from Attlassian support in regards to this:
Thanks for contacting Atlassian Support.
Looks like you have encountered the issue https://jira.atlassian.com/browse/JRA-43836. We've checked that restarting the instance doesn't fix the issue this time, so it won't be necessary any downtime. We already have the developers working into this, and we'll contact you again as soon as we have any updates.
Thanks for your understanding,
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