It looks like a combination of the pandemic and the closing of the hotel where the event was traditionally held.
https://www.chess.com/news/view/gibraltar-2022-battle-of-the-sexes
https://en.chessbase.com/post/battle-of-the-sexes-in-gibraltar
Reported last year that because the long-time location of the festival was permanently closed, it was being replaced by the Battle of the Sexes, a 10 board event.
Since the Caleta Hotel was demolished last year, the festival is without a home.
The final report from the Battle of the Sexes hints that there are intentions to eventually return the festival to Gibraltar but said there was nothing official.
This has been a January event for years. All I can find on the web is descriptions of the event of previous years. The official site says nothing about 2023.