Got the new Forte and my first attempt at FP with 30g/500 g at 203 resulted in a fairly smooth cup, uncertain about the taste at this point being the first cup.

I was following a 4 min initial, followed by 5 mins. However, I noticed that after the initial 4 mins, all the grounds had fallen leaving nothing to stir or remove. This is something i've not seen in videos or read about in articles.

Is this indicating that a parameter needs adjusted?

Could be bean freshness. I'm thinking it the gasses in the beans that keep them floating and forming a "raft". How far past roast date were they?

Depends on roast level as well. My light coffees settle faster while darker roasts can stay a float longer. Staleness matters too.