I have no idea what's going on there but I've noticed the same thing. It's very strange that there have been times I couldn't match a $150 bet on an English Premier League soccer game where I was offering 2c better than Betfair, yet I can get down 20k on an NBA 2h spread where the split is only 2 cents, i.e. I could get +106 on one side for 20k or -108 on the other side. I know Matchbook is more geared towards Americans but there are plenty of Americans that watch the EPL.
I think part of the CBB problem might be that Matchbook can be slow to adjust lines, so people might not want to bet there when they're hanging an off number. I had trouble matching Georgetown in the game vs Syracuse because MB was either hanging +5 or +5.5 when the market was +6.5, and perhaps people didn't want to bet the off number.
