Medium seems to change their various algorithm formulas as the begging of most months. They definitely changed things in February and this affected compensation and lowered the acceptance percentage of Boost nominations. It seems that the February changes hit everyone fairly equally. But I don’t see it as a long-term downturn. It was just a bad month and these happen every now and then.
On Medium's feed, it has ALWAYS been terrible. You absolutely cannot rely on seeing articles from authors you follow. The only ways to be sure to see them is to subscribe to authors' e-mail notices and bookmark their author page and check it daily.. That's what I do, because Medium's feed is worthless and they push meaningless articles to us.
I wrote this yesterday about one phenomena I see from which all authors suffer.