Not unusual for oil to creep up securing bolts. I believe one or more of the threaded holes they screw into are not blind, but pass into an oil gallery. Good case for not being tempted to run engine with cover off!
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
