Hi Dave
In my opinion you had a head gasket problem.
If you suddenly lose ALL compression in 2 adjacent cylinders, and suddenly have water in the oil, pretty much has to be the gasket.
I don't think you would lose that much through a crack.
The people you left the head with should check the flatness of the gasket surface as a matter of course.
But ask just to be sure.
You might want to check the block surface as well, but you will need a special straight edge for that (not just a carpenters level 🙂).
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