If there is an innocent explanation, I'd love to hear it, because it kind of reads like the force push was done to move the commit with the attribution change out of the public eye so it wasnt clear what they had done.
Maybe it is possible the google engineer didn't understand how open source licenses work, or didn't care since maybe it was supposed to be an internal project first that eventually ended up open sourced?
Given the replacement author and email seem like a random person rather than an employee, I wonder if whomever did this thought they had found the "real" author and that somehow the others were incorrect? It's confusing, I don't know.