Unexpected still behavior

[Yunus]

I had something unexpected occur during distillation and wanted to get some expert opinions and advice. I run a condenser control still built by Manu. It's been reliable and consistent and awesome (highly recommend Manu), I was running in pot still mode (no packing). Anyways, I was running 10 gallons of 5-6% apple cider. When the still heated up to just below 80C I started getting results so I turned the heat way down on my propane burner ( I use a sankey keg as the kettle). Things went a bit slower than expected and the temp starting increasing after only 500ml of product. This continued until the temp was around 96c when I only had around 1 liter of product. This seemed unusual, so I made sure that I was cooling enough and that nothing was escaping in vapor form which it was not. Then I decided to turn the heat up on my burner, this decreased the column temp to 80c. I ended up getting a gallon of usable product at 150ish proof.

What I don't understand is why increasing the amount of heat energy applied decreased the column temperature? Any insights on this, I'm pretty new and I know this is an art as well as science but I'm really interested in the science behind what occured but in laymans terms if possible.

Thanks!