Something went to hell here… This is the first time I have encountered this. Weird that everything seemed OK at the beginning and end of the roast. While roasting I thought that this might be the result of the inlet temperature banging against the 700F limit I set but clearly there is an instability here. Normally roast should stay below the 700F inlet limit so that end of the control algorithm is not in play.
Coffee turned out OK. Still not liking this Guatemala all that much but I don’t have all that much more to go through.