Many times when there is light contact between the valves and pistons, with the valves hitting the pockets nice and square, it will barely tweak them..... To the point where you can't even see it, but they leak. When you reface them you notice they have been tweaked.

Apparently there was quite a bit of p/v clearance, otherwise it should have tagged them harder, which would mean a higher leakage %.

Just cuz I'm curious, I would have stuck a pair of lifters and rockers back on it and done a compression test on a couple cyls........ Just to see.