This paragraph was taken from the Bel-Ray website. Link
https://www.belray.com/2-stroke-lubrication/
Ester based fluids will withstand great amounts of heat and will not burn in the combustion chamber. Since they do not burn, the emissions are clear of soot and ash that are commonly found when using lower grade lubricants. These esters naturally adhere to metal surfaces and create a very tenacious film, so when the lubricant is brought onto the piston, it creates a film and spreads along the surface to protect the entire component. This film is difficult to eliminate, therefore, the engine will remain lubricated through very harsh conditions.
bwalker's comment
The only oil that's in the combustion chamber is the small amount above the piston rings and excess that is forced up through the transfers. This oil must combust cleanly and fully or you end up with all sorts of problems such as exhaust port blockage, fouled spark plugs and stuck pistons rings.
Seems like a contradiction. bwalker, you say the oil combusts Bel-Ray says it does not. You also say only a small amount of oil is above the piston rings. I contend that all the oil in the mix at some point in time is above the piston rings.