My buddy put his over on its side last spring, and never thought any thing over it. We pushed it over. The next ride out, every steep angle his bike would smoke badly; but on flat smooth ground there was no smoke; he had a puddle of oil in the airbox that would slosh around on rough uneven terrain or steep hills. A good cleaning of the airbox, and a new filter resolved his issues. I put mine over on its side last fall, but immediately pushed it back onto all 4s, I had a small amount of oil end up in the air box. There was a couple of posts last year about oil in airbox and never have flipped their machines, I believe it was attributed to too much oil.
I had a post in XMR forum on Sunday same issue. Narrowed it down to Dealer overfilled at 10 hour service. I got about 2 cups out. Check your oil level when engine is cold. If it's like mine it's likely still a little high on the dipstick.