Manuscript status changed from "Reviews completed" to "Editor assigned"
I think @ShakeBaby might have nailed it in the "whatever" comment.  Best guess: reviews came in after all this time but were inconclusive, and "editor assigned" is the default state when needing to get more reviews and no reviewer has actually been assigned.  In ScholarOne this would be like having it set to require 2 reviews, then when the 2 reviews come in, changing it to require 3. 

Certainly not a very informative status.