What is going on with these rod bearings?

You confused me at "disquieting".

I thought it was a mistake. I was wrong. This is a real word:

Dictionary
dis·qui·et·ing
/disˈkwīədiNG
adjective

1. inducing feelings of anxiety or worry.
   "he found Jean's gaze disquieting"

I've torn down a few original engines and have seen the same thing. I attributed it to water/acids in the oil from condensation.