Magnum camshaft bearing mystery

I have 2 360 magnum motors that I purchased used. Both have over 100k on them. Both were exceptionally clean inside. No sludge, cylinder wear at a minimum, etc. When I went to change the camshaft, Both had weird wear and damage on the #4 cam bearing " see pics"

View attachment 1715928665 View attachment 1715928666 No damage found on either camshaft. Just curious if anyone else has noticed something similar and maybe an explanation.
I just rebiult a 5.9 magnum same thing #4 cam bearing was bad.