Should the GSH25JFXB enter a pre-phill mode prior to defrosting? Everything I've read about the GE Adaptive Defrost mentions a pre-chill mode where the temperature dives 15 degrees before the defrost heater is activated. However, my fridge is showing no signs of this. See attached temperature plot, purple trace. Should this fridge model be performing a pre-chill before defrost?

Background: I am debugging a defrost problem. The defrost cycle is melting things, including ice in the ice drawer and causing ice buildup. I've seen temperatures as high as 80F during defrost at the evap thermistor and at the top of the freezer near the ice maker. The bottom of the freezer, near the thermistor, has also gone as high as 40F during defrost. Details:
Debugging Refrigerator Problems | Iowa Scaled Engineering, LLC

So the reason things are melting is clear, but the reason it is getting so hot is not. The lack of pre-chill seems possibly a contributing factor, but I have not found anything conclusive that my model should do this.

Thanks for you help,
Michael