[mr0077]

I'd expect stripped threads (not a real good thing) before cracked bowls IF you damaged the bowls...either way it means new bowls I think.
I would bet that the nuts backed off when you tightened the flare nut on the inlet pipes. Get a backup wrench, hold the bowl inlet nut, loosen the flare nut, tighten the bowl nut firmly then hold in place while you tighten the flare nut...don't let the bowl nut turn in the tightening direction when you tighten up the flare nut, and see if that fixes it.
Let us know.