I've been concerned, too, since Devers has been one of my prospect binkies.
If I were to place a guess, it would be that the Sox are challenging Devers to move past see-ball-hit-ball and onto building a disciplined approach at the plate. Which is perfectly reasonable, except that Devers is also the third-youngest player in the Carolina League.
Now, that would be IMO a necessary step in his development as a power hitter, since his isoD was genuinely horrible last season. Without building a disciplined approach, the pitchers will eventually be good enough not to make mistakes he can punish, and he'd end up buying a ticket on the Wily Mo Pena train to Japan.
My guess is that if he were turned loose to just swing away, the numbers would readily improve. But that might be worse for him, in the long run.
This season the thing I'll be tracking for Devers is incremental improvement month-over-month.