Defragmentation example: they have a team with 12 people in California, 5 in New York, 2 in Seattle and 3 in Zurich. They decide to move all roles into one location instead of having the team split all over. If you don't want to move with the role, then you need to find something new.
Alternatively perhaps they just merged some teams and there were surplus folk. In my experience (unrelated to any of this) in rapidly growing orgs, teams/functions often get duplicated/semi-duplicated as different parts independently spin up teams to deal with some need. Ultimately these end up getting rationalised as time progresses.
If they were doing big layoffs of engineers etc, I think we'd have heard about it o we Twitter/blogs/comments/etc by now