You must be new here. Many companies keep ex-C-levels nominally employed as 'consultants' so their stock can vest (which is typically the bulk of their compensation) and avoid any expensive/public lawsuits. It's paying them off to quietly go away without spending any cash.

This isn’t the own you think it is. C-level execs are often contractually obliged to serve out lengthy notice periods, a quarter and some change is nothing unusual.