I'm flying on Air Premia PE for the first time this week (EWR-ICN), but judging from FR24 and their "notice" listing page, their operations have been ABYSMAL since mid-March.

From some Googling it looks like they're running into problems inherent to having a small fleet, and also newly-delivered 787s with mechanical issues:

Air Premia faces backlash for poor service and aggressive expansion amid flight disruptions

Air Premia expands routes to Hawaii while managing aircraft defects

Their PE product looks great, and the price was right. But if they pull any last-minute scheduling nonsense (or try to rebook me in regular Y on KE) I've already decided to take the refund and fly CX PE instead.