It's likely they have "whisperers" in games
While chatting in sofascore room you will find plenty of whisperers commenting live that this match is sold, X had sold this match to Y. But as soon as the results are near they are offline and we never hear from them. Frankly i would ignore such whisperers.
I also supported what you said because a strange don't worth to be trust cause they are the same as the online crypto traffic group which make false news in other to pump the price of their no potentials holding.