You need at least one capture sequence with 2 Frames in a row to get the boolean isTemperatureDeltaCheckActive become true.
In my case the Capture group was 1 Frame Ha, 1 Frame Oiii, 1 Frame Sii, 1 Frame Ha, and so on.
Because of this, the isTemperatureDeltaCheckActive will never be set to true and the focus delta is not checked. Maybe it is enought to start with two short captures, f.e. L-L-S-H-O-S-H-O-S-H-O becuase the isTemperatureDeltaCheckActive will be only resetted when you uncheck the checkbox.
The only "driver" issue that may be changed is that the driver debounces the temp updates by 0.5° of temp change, but this is also done by myfocuserpro2 ...