Everything is possible in this country, even that which is very illogical and suspicious

But I dont think that there was such a reason - bookmakers have the right at any time to declare any result unplayed and return bets to betters. This is done to protect them from such fraud.
The strange powers of the bookies. In this case, they may try to declare any suspicious match invalid. Especially if they suffered losses on it.
There should never have been a match like this.
If the bookmakers did not have such a right that protects them from dishonest matches, then all legal bookmakers would go bankrupt for a long time. There is a lot of situations where fraud (in sports) is obvious, but it is unrealistic to prove collusion. These rules help bookmakers protect their business.