That is absolutely correct.If it had been "clear" then VAR would have given it as it would have been a clear and obvious error. But the fact is that it wasn't "clear" as there was sufficient doubt about where the ball had actually hit Rodri and whether it was mostly in the red or green zone.
The laws are the laws, however daft they may be, and on that occasion, as with Ederson at Arsenal and KDB at Southampton, there was doubt so the original decision wasn't changed.