Doesn't sound right, I have 5 bikes, KTM, YZ's and CR and none of them leak out the drain plug. I would check to make sure you are not missing an Oring, or if you have a copper washer on them for sealing, either replace it or re-finish it. (wet sand on a flat surfuce ).
Are you sure they are dripping out of the drain plug or is it leaking somewhere else and that is the lowest point?