Well, if a spare dist is behaving exactly the same then it can't be in the distributor. I think somehow the distributor drive gear came up a little and jumped at least 1 or 2 teeth over then dropped back down when you pulled it the first time. Put it tdc again and pull the distributor then see where the drive gear slot is clocked. Then hold your distributor in roughly the same position and see where your rotor is pointing.
I'd be curious to know what your timing reads now if you were to move the pickup clamp to plug wire #8 or #2, or even #4 or #7.
I don't know if that would help verify if the gear could have jumped over or not. Just trying to help