I have a theory that they're simply throwing shit at a wall and hoping for at least some level of engagement with sections few of their users actually give a shit about.
See also: Non-chronological timelines
This is a sign of a design team in crisis.
Mayer's engineering and metrics first 41 shades of blue color fiasco at Google comes to mind
Or just that different features are available or relevant in different locales, seeing as they service... how many countries?
I think this could go 1 of 2 ways.
Either they're trying anything they can to desperately increase engagement after seeing some alarming trends in the user data that will not bode well for future ad sales....
...OR, they're moving on to something bigger and better, the end goal being an app that slowly shifts to meet the differing needs of individual users.
I love this thank you.