I'm continually having this same issue with my MCR1500 digital. I lose BT, IT, and or ET continuously as I'm roasting. It's gotten worse with this latest release.

I'm seeing something similar on my 2kg digital. I'm assuming it's two different probe readings. The one in the door is read by roast path and the reading on the machine is coming from the second probe to the left of the sample spoon. I can see this when I open the door, the temp on roast path cools, while the machine temp stays hotter. I'm also seeing fluctuations in the difference between the two temps based on closing the door, how long it's closed, the beans wrapping around it, etc. So, may be way off base, but that's what it appears like to me. Open to correction for sure, and a way to make these read more closely if they should.

Also, open to better understanding which temp to operate from, roast path or machine reading? Thanks!

Curious about the response on this one. I'm having the same issue at settings below 1200.