The RDU route has been extended from October 2022 until January 2023. FI's own website and ExpertFlyer shows the flights running until the first week of January.
There is a news article stating the flights will run until January 23rd, but it's possible that the news site interpreted the "January 23" information in whatever communication FI put out as a date, not January 2023.
The previously communicated plan is to resume the route in May 2023 together with other seasonal routes.