Ignoring the pointless anti-Semitic remarks above, yes, I noticed the same things about the bets.
How are they even explaining that Ippei was allowed to get in the hole $40m?
There's only one way I can see this happening.
Ippei lied and said he was doing it for Shohei. He got way in the hole, and begged Shohei to cover $4.5m, which was actually just a fraction of what he owed. Then he got Shohei to send it to the bookie, thus making it look to the bookie like it really was Shohei's bets. Then he kept firing, and got as much as $40m in the hole. He stole the other $11.5m via impersonation to wire the money, and then the bookie got busted and he never paid the rest.