Same, from FAANG companies. The feel that I get is more like, FAANG companies don't even know what you're going to do. They just want to hire top talent and figure out what you're working on later. They want someone "smart" who can ultimately work on any team, since whatever team you initially land on might be gone in a few months.
The consequence of this made the interview process for these companies feel much more like a "drinking the kool aid" test. When I asked what I would be doing, the sales pitch I got always boiled down to "you'll be working for X" as if that was enough. That might be enough for a fresh grad, but I'm an experienced specialist. Understanding my role and impact are key to my job happiness.
I don't think the intent is to be secretive, its more about - the people in the recruiting pipeline don't even know themselves, or if they do, you might get rearranged quickly, so focusing heavily on the specific work is more of a detriment. You kind of NEED to drink the kool aid since you're buying in to the company moreso than buying in to a specific team, work, etc..