In order to ensure that we are managing the Book responsibly, we will sometimes limit our amount of downside when one side of a bet gets a lot of action. Unfortunately the bet in question is very popular, so you've hit this limit. We have some plans for tweaking our risk management, such that it will be less likely that you hit these limits (though they can still happen sometimes). In this case you can still get action down on the full game, just not the half bet.
This actually gives me much more confidence in you. Obviously, it will be an issue for last minute bets, but for a small book, this is a very wise move. I like what I see so far in my games I've bet today. One recommendation would be to add a description of the bet for pending bets.
For instance, if I bet NYG 1st half AND a separate bet for NYG full game, I can't easily tell what the bet is for. I do keep my own records, and usually it should be easy to tell with the point spread, but it's just nice to see it in the pending action.
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Great quick response! 