Peanut Butter ...??

This has me somewhat mystified ...
When-ever I check the oil level in the stock 318 in my '72 Coronet , I find a smattering of the dreaded "Peanut Butter" at the very top of the dipstick (!!)
The crankcase oil is normal ( no discolouration , normal fill-level , etc. ) , but that damned Peanut Butter that's only at the top --near the handle-- of the dipstick behooves me !

Any ideas ?
Ostensibly , condensation's getting-into the motor some-how ; more than 'normal' moisture .

I replaced the head gaskets 2 and 1/2 years ago (along with the intake gaskets ) ; used Perma-torque gaskets (metal / composite) ; used copper adhesive ; all head dowels were in-place ; all retainers torqued in proper sequence and to their lb/psi specifications ; and it's been 20,000 + miles .

Timing Cover is new , along with its gaskets / seals ( replaced back in July ) .
Cooling system is a mix of G05 and Distilled Water .

Car never runs hot , even in hot weather / extended driving / extensive idling .

Please advise .

Thank you !

[email protected] attn : John re: coolant .