I know a few users have stated that this is a shady practice or borderline. Well, most gambling sites have it in their terms that if a bug has been found whether it is known by them or not that the bet would be refunded, and not paid out. As Suchmoon points out Roobet also has this written in their terms. Gambling websites are perfectly in their right to wave off any bet that was the result of a bug within the system, and refund the initial bet amount. Instead, Roobet actually paid to the maximum win which I think is the best possible scenario in this.

You could argue that this is common sense to not allow users to bet if the amount goes over the maximum win. However, several bigger gambling sites allow you to do this. If I recall correctly Skybet  used to have a cap of 100k on certain sports. The return will always show that you are going to win just 100k, and not over which seems to be the only difference here. For example, if you were betting £20, and it displays the maximum bet is 100k you can still bet more than that on their website. So, in theory you could bet £25, but it still displays the win amount to be 100k.

The only difference I can gather from this discussion is on Roobet it displays that you'll win more. However, if they have stated that their maximum bet is x amount then the normal process that other gambling sites would have taken would have been to apologize, and refund the original bet amount rather than paying out for the win. This is subjective, and can sometimes lead to users feeling outraged, but what has happened here is one of the better outcomes of this situation as per their terms which you agree to when signing up, and using the website they don't actually have to pay out if the bet is subject to a bug of the system.

It is an annoyance for the customer, but if the customer knows about this in advance, but still bets knowing they would only be paid the max bet amount then that isn't any better than a gambling site which has it in their terms that they will only pay out to the maximum bet amount.

If you had lost the bet amount then that would have been a different circumstance, and would have been a even bigger shitstorm, because if you knew that you could potentially get that bet refunded, because of their policy of only allowing a certain amount to be won then the gambling site could suggest that you purposely bet over the amount just in case you lost, and have the potential to get a refund, and not lose any money. I'm not suggesting that is/was the intention, but that would have been a moral debate that I think a lot of users would have been split on, because there's two sides of the story.

Roobet have now fixed it according to this discussion so this can't happen in the future so something good has come out of this discussion at least. You have been paid to the maximum win amount, and Roobet have at least honored that where other gambling sites with less integrity would have likely refunded it.