Ok, just figured out the solution, at least for me. Noticed that the new version of Procreate (5) was loading my PSD brushes when airdropped. So went into ios settings and offloaded the Procreate app. Now Artstudio is recognizing the .abr brushes which before were greyed out. This is a workaround and a hassle so I hope this gets addressed. So I'll need to collect all my brushes to import at one time, batch import them and then re-turn on Procreate so I can use it. Hopefully, v.3 fixes this problem.