TS, I'm on the cruise after yours, and yes, we were supposed to board in Manila. The reason given to us for the change in embarkation port to Hong Kong was that the port of Manila had operational issues affecting turnaround.
I've also noted that the Norwegian Sky departs from Manila in January 2025, and that this cruise is still available for booking today. Either NCL expects the operational issues in Manila to go away a month later, or is just waiting till after final payment date for that sailing to issue the change notice.
🤔