The only thing I'm really concerned about is the cam lobes starting to go flat on the high PSI cylinders (1 and 2) and reducing duration and increasing dynamic compression which could lead to detonation (I think).
FWIW from the (fortunately) few shot cam lobes I have seen, they have all gone at the toe, or peak, of the lobe. No damage was done on the far flanks where of the advertised duration is set duration is set.
I am going to guess that you have some soft lifters there; you're hardly getting the pressure built to pump pump up the lifters. Or the cylinders sealing super-good for some odd reason. 20 psi is like another point in compression ratio....
If you do the timing, check it on #1 and #3, or #2 and #4, to see if they are different by exactly some multiple of 90 degrees.
