Ummm. . . . yes. . . .
That gray paste is probably part of the additive package -- moly, if your spec calls for moly, since that seems to fall out of solution readily and appears as a gray paste. The moral of the story is to shake it, shake it good, before pouring.
Molybdenum dithiocarbamates don't fall out of suspension that easily. If a motor oil needs to be shaken well before being put into service it is the product of an inferior blend process and I would be switching brands in a hurry.
