Rico was saved by spitting out his mouth guard

Please explain the relevance of "my alpaca has a giant knob!"?

 

Not sure why everyone thinks randoms on twitter are some kind of authority when they can't even get the basics right. You can clearly SEE the timer go down to 9 seconds before the ref calls time out for the mouthguard. Then once action restarts you can count the 9 seconds before the bell goes. It did not ring 7 seconds earlier, sheesh.

 

It does seems like there are grounds for a NC.

Maybe it doesn't need to be a grand conspiracy, and it was just referee error(s),

As you mentioned, by the rules, the gum shield incident may be worthy of a point deduction. But that is it. The referee was obliged to get it put back in, again going by the rules. Maybe not deducting a point can be seen as an error.

but finally it was an error that gave the win when the fight was in the balance.

Usyk is pushing for the finish. Rico is trying to defend and throw back. Very normal.
The referee gets into position with the round ending. Still normal.
The bell went, and he stepped in breaking up the fighters. Quite normal actions.

Then to everyone's confusion he is waving it off.
Waving it off after the bell is the issue. His reason being he didn't hear the bell. Which means he knows he made a mistake, and yes it explains his error, but it doesn't excuse it