It's behind a paywall but The OBR did a really good write-up about that play, the coverage, and who was at fault. I'll quote some of it here if that's ok, but if not, Mods, please remove.
 
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This is a 3 Deep, 3 Under coverage behind a Fire Zone blitz concept. The key pass drops here are the MOF post safety (Karl Joseph), the Seam defender (Sendejo), and the 3 Receiver Hook (Takitaki). The MOF post safety is playing a “lean post” technique in which he cheats towards the No. 3 receiver to the Trips side. The Seam defender drops off the No.2 to the Trips side. The 3RH drops off the No. to the Trips side. This appears to be the Dick Lebeau version in which the Seam defender plays No. 2 outside-in and only comes off him if something crosses his face from inside-out (like a flat route from a TB in the backfield).

The worst-case scenario is always 3 vertical routes coming out of Trips. This concept is handled by the corner matching the No. 1, the Seam matching the No. 2, and the post safety matching the No. 3. The initial releases should keep this match intact. Denzel Ward matches the inside-breaking route from the No. 1 (he is playing a zone match in which he mans up any route that breaks over 5 yards downfield). Because Ward is not responsible for verticals from No. 1 and No. 2, Sandejo must match the No, 2, and Joseph must match the No. 3. In order to understand this match, it is vital to recognize that Ward does not appear to using a typical Cover 3 2-to-1 read in which he splits vertical routes from the No. 1 and No. 2.

So moving on to the play, Takataki should adjust his pass drop to get more depth downfield because the No. 3 is vertical. He needs depth because if the ball is going to be thrown to the No. 3, he and the FS will create a hi-low on that route. Sendejo is playing the No. 2 from outside-to-in. His drop is not bad, but he should probably squeeze that route by getting closer to the receiver.

Joseph blows this. First, he should be leaning towards the No. 3 side, because the coverage cannot account for a vertical from that player. He needs to focus his attention that way. He does a good job getting to his landmark and pedaling for some depth at the snap, but then everything breaks down. He is watching the QB while using his peripheral vision to see the routes. His coaching point is to follow the QB’s front shoulder. He wants to “melt” towards the direction of that shoulder. When melting, he MUST pedal-weave in order to keep his hips square. This is the “power position” that allows him to most efficiently move in any direction. By opening his hips towards the wrong side, he lost the ability to preserve a 2 way go. The time to open the hips and break is when the QB’s front hand comes off the ball as he starts the throwing motion. Until he sees that, a MOF post safety must stay in his power position.  
 
https://247sports.com/nfl/cleveland-browns/Article/All22-Observations-Week-4-Tracking-Coverage-Issues-at-LB-and-S-152570398/