Yes, just weird. Oil doesn't separate like that. Sometimes people report some additive fallout settling solids (small amount) to the bottom of a jug or bottle, but not this phenomenon.
As said above, maybe shake it up really good in the jug and immediately pour the mixture into a clean empty glass jar for viewing later.
Shake up a bit together (to make sure the clear part mixes with the brown part temporarily) and put it in a solid jar, pad it like crazy, put in small box and mail to Valvoline after they give you a routing address via a contact there.