i think you're right that something has changed. Aer Lingus has usually only released a handful of biz seats at around 330 days out, then held back everything else for their own elites and for avios or bid upgrades

Very occasionally, you'd see 1 or 2 seats made available a few months out for a handful of flights, but never more than a handful and never more than 1 or 2 seats. I do remember seeing a few seats in December last year for NYC flights in January/ Feb as I was planning to travel around then - I remember it because it was unusual.

What you're seeing may be Aer Lingus getting more aggressive about releasing seats a few months out; It may just be an experiment; it may just be a once off as Feb is a really quiet month. I don't think anyone here will really know, as it's not really something that's happened before at any kind of volume like you're seeing.

Will this mean seats of March and April will be released in a few weeks? No idea - we really are in uncharted territory right now. I wouldn't bet on it though.