Overheated soy smells scorched, looks a bit yellow or grey, and throws worse because you have cooked off the light notes. The wax still sets. It just sets uglier and quieter.
What “too hot” means in practice
Soy is happy well below the temperatures people use for paraffin. If you are heating until it smokes, you have missed the point. We melt what we need, add fragrance at the temperature the oil actually wants, and pour. There is no prize for a rolling boil.
At home
If you burnt a candle so hard the pool smelled of burnt sugar or dry paper, that is a wick and a draught problem, not the soy being “overheated” in the making sense. Trim it. Wick trim.
If you are pouring your own and the wax smells like a chip pan, bin that batch. Do not gift it. Start again cooler. Our finished jars — Skye and the rest — should never smell cooked. If one does, something went wrong in the burn, and we would rather see a photo of the flame than a one-star about the wax type.

2 comments
Anita
When using biological C-Blend soy wax, what is the melting point or maximum temperature you can heat
HCC
It can vary slightly depending on the specific formulation, the exact info should be provided by the manufacturer. If you have the specific brand and type I may be able to help