no- i don't think it's out of the question to start producing colostrum this early. it hasn't happened to me yet, but i think it's relatively common to start in second tri. i'm sure there are tons of reasons why one would leak and not the other. it may be something as simple as the way you were sitting.
i wish he wouldn't call it gross. it's not what he's used to, but in a way it's beautiful. your body is preparing to feed his baby!