There is some sort of team reshuffle, someone moving to a new project and so on. Another team agrees to take on a high level IC (I assume this guy was at least L8-9). At that level, this move is approved by a VP. Person moves, headcount is filled/removed at his old team. Then new VP decides he is not ok with some part of the working arrangement (e.g. remote, scope). Person is now given a few weeks to find a few project/team, but most teams cannot accommodate senior ICs at that level easily.
Boom, out of a job. Basically VP backroom dealings. It's just 'bureaucracy', and seniority almost does not matter. The only way to stop it at that point would be calling other VPs or SVPs for favours.
In fact, seniority works against you here, because it becomes more political, while nobody cares about a low level IC switching around, and almost any org can absorb a solid L5 contributor.