Agree with jeff... frame geometry has a lot to do with that. Some bikes are really poor designed. If the OP can ride no hands in anything else then is the bike.

I have a similar problem with the only hybrid bike i have, havent been able to ride no hand confidently in that one ever. I blame the headset that is garbage and clearly the headtube needs to be chased again because is horrible bad finished. Geometry is ok but not confident in that one at all.