The Wikipedia page on Sziklai pairs contains the following statement (emphasis mine)
Sziklai pairs can also have the benefit of superior thermal stability. [...]. [Q]uiescent current is much more stable with respect to changes in the temperature of the higher power output transistors vs the lower power drivers. This means that a Sziklai output stage in a class AB amplifier requires only that the bias servo transistor or diodes be thermally matched to the lower power driver transistors; they need not (and should not) be placed on the main heatsink
I'm specifically interested in the "should not" part of that statement. I suppose that placing the bias transistor on the main heatsink may be overcompensating, which could create distortion at normal operating temperature? Or is there something else at play? Does this mean that I should make a separate heatsink for the lower power transistors so that they can be thermally connected to the bias servo transistor?