Water Heaters - New water heater leaks, pilot light goes out

2 years ago I replaced an old gas water heater with a new GE 40 gallon from Home Depot. 2 months ago, the drain pan filled up and the pilot went out. No obvious leaks around pressure relief valve, inflow or outflow pipes or valves or the drain valve. It was under warranty, GE replaced it (I installed it). 2 months of perfect hot water and now the pan fills again, pilot light goes out and I can't find the leak. I suspect the pressure relief or drain valve but cannot verify my suspicians. I assume the hot water heater has a protective mechanism when water reaches a certain height in the pan. It seems difficult to believe the tank has broken 2 times on a relatively new water heater. Where else can water come from?

I don't think any gas water heater has a safety mechanism that shuts off the pilot when the pan fills up. I'm wondering if the TP valve is releasing hot water, which is flashing to steam and the steam displaces enough air to extinguish the pilot light? It seems odd that its leaking enough to fill up the pan, but you can't see any dripping or other evidence of a leak.

How hot is the heater set for? Also, do you have a pressure reducing valve on your water service or an expansion tank? Has the water department installed a backflow valve recently on your water service? It sounds like thermal expansion may be causing the TP valve to trip momentarily, and the steam may be suffocating the pilot.