Ok, so I did notice a small drop in likes over the last few days but I am not basing the assertion on that. I have 5 accounts, 4 are perfectly chronological. The fith is showing some stuff from the last few seconds or minutes on top mixed in with posts up to a few hours or more old. My guess is they are just testing on a subset of accounts. If that's the case and people are already noticing engagement drops, then it doesn't look like a great sign! However, my best engagement account has been outperforming the last few days so who knows.