Pending the software patch, given the independently controllable set points, it may be possible that the PID parameters are potentially optimised for the boilers. If I am correct, the 1C undershoot was t3 (group).
From the threads, I am not sure how the users have addressed the temp offset between the group and the boiler. I remember at least a couple of users setting the group a degree to two higher than the brew boiler.
It will be interesting to see what the temp oscillations be from the set point if one were to set the brew boiler at, say for an example, 99C and the group at 93C for a medium light / light.
At the moment, I think the boiler temperatures are in steady state / equilibrium at the set point.
I am also thinking if they implemented some sort of dynamically adjusting (self-correcting) solution internally to reach system to converge to the set points, given the PID parameters are common for all temps? Is that the Delta (Es)?
Otherwise, how could a set PID parameters facilitate 3 different set points? I see this more as a loop (set points, PIDs, actual temp + correction). Dave may be able to shed light.