How to diagnose radiator fan failure?

[sasha055]

I think my radiator fans are acting weird.
Yesterday it was 85 degrees in Seattle (Winter in Texas is warmer than Hot Summer in Seattle) and my coolant temps ramped up to 106C
10 min after parking the car in the garage coolant started boiling and overflowing.

Here's what I tested:
1. Coolant Cap is new, I replaced it 6 month ago.
2. Before yesterday I didn't loose any coolant and there is no condensation on rear trunk lid
3. Radiator fans turn on when I start AC and both of them are working properly (napkin was stuck to the grille on both sides)

Now the weird part:
4. I started the car and waited for it to warm up and fans to start. I watching the temp on AC LCD.
Fans started when temp climbed up to 103C (217F), engine cooled off quickly and fans stopped when engine cooled to 99C (210)

I thought fans should start at 96C (206F)

Is it normal? are my fans broken? if yes what is the fix?

Thanks
Sasha