Didn't see it so gotta ask,, did you change/clean the clutch oil jet?
Not that it would matter that quick after starting..
If you put it in 5th gear, will it move without turning the motor when you pull the clutch lever in?
I tried a full synthetic in my old DR30 years ago,, it did the opposite, I had to drop to a blend to make the clutch not slip... Took a while for it to recover..