This happen to an old warrior we had....the sealantis a temp fix....too much of a risk for me as the bolt on the bottom of the case and any loss of oil will not be noticed until the engine stops working out on the trail.

I had a shop weld it...drill out the drain plug threads....grind it flat and re tap it....yes the bolt was no longer stock. But it did not leak either.

I guess rtv might work....it just scares me is all.