lots of output all at once followed by temperature spike

[RumRaider]

Hi,
I can't find the answer to this anywhere else and am hoping someone can help.

I was running a 4 Gallon fruit based wash through a brewhaus 8 gallon reflux still (on full reflux, hooked up per manufacturers instructions). I had just cleaned it by rinsing and then distilling a few gallons of water through it. Things were progressing as usual (this was only my 4th run overall so "as usual" is a relative term). I was getting 1 drop to several drops of foreshots per second and temp reading was stable around 178F. After a few minutes i realized the rate of drops was fine but the drops were smaller in size than usual and it was taking a long time to collect a small amount of output. I turned the heat up very slightly thinking it might speed things up a bit. The temp went up to 184F but the output went ballistic! Immediately the output was a steady and FULL stream and the jar filled up FAST, the still just burped out distillate at an incredible rate (it started with maybe 3OZ in the jar and finished at about a full pint in just two big burps) and then went back to normal. I quickly changed jars and went back to 178F and a more normal output. I figured "fine, i learned a small temp change can have big results" and pressed on. Then it happened again several times without me doing anything. The temp would slowly drop to as low as 169F, there would be a big surge (burp is the best term i can come up with) in output, followed within 1 second by a temp run up which would peak at about 181F. Then it would return to normal (174-178F and one to a few drops per second) for awhile then repeat the cycle: temp decrease, big burp with temp spike and return to normal. Again, i didn't do anything to the heat after that first time, it just happened on its own several tmes. I made cuts in pint jars and when i finished i had tossed a pint of foreshots and was left with 5 1/2 pints of hearts and tails. I then tested using an alcometer and the jars were 75%, 62%, 58%, 45%, 38%, and the last 1/2 pint jumped back up to 62% (triple checked it).

My questions are:
What caused the "burping" (and is there a better term than "burping")?
My prior runs had higher %ABV (started at 92% after tossing foreshots), could the burping problem also have lowered the %ABV of my output?
How could that last 1/2 pint have gone up in percent ABV?

Any insight would be much appreciated as i'm baffled and worried that the burps are also a safety concern