It's always been like during February I'm pretty sure
4 months every year they have 5 week EQs because there's 52 weeks in a year
Maybe because the lunar new year quest starts next week, so they didn't want a new SQ starting the same week?
This is correct. 4 times a year they need to have a 5 week EQ to use up the extra days otherwise we’d end up with 13 monthly quests per year