The starter clutch will sometimes make that noise regardless of what brand, weight, or type of oil you run. I have had a variety of synthetic, semi-synthetic and conventional oils in my engines and they have all done it on occasion. It's just the way these are. I am currently running Rotella T4, which is a conventional oil, and it did it to me just yesterday. It's not a big deal, don't lose any sleep over it.
1990 EX500 - 141,000 miles as of June 30th, 2019
1993 Ducati 900SS - The real canyon carver
2002 EX500 - Undergoing a full restoration