Both Aurigny and Blue Islands seem to (from local media / social media posts) have issues with their new routes to/from Dublin from the channel islands. Apparently to do with Brexit issues / operating licences. GR have a temporary licence until first week of April according to facebook posts, whilst Blue Islands weren't granted a temporary. Both flights appear to be operating / will operate into Belfast.
From social media posts Blue Islands seem to have handled the situation very well providing onward transport to Dublin from Belfast, and inbound to Belfast from Dublin.