My wife's Pantech Burst has had an issue with overheating and completely draining the battery within a few moments. This has happened 3 times in the last 3 months. The 3 events were each several weeks apart.

This is not the normal "gets hot when charging or during heavy usage" or "the battery drains within X hours". This is something much more EXTREME than that.

All 3 times, the phone has been in her pocket, with the battery level between 80 - 95% full. All of the sudden, she feels a very high heat in her pocket (~120 - 150 deg. F - I measured this temp with an IR thermometer that I use on motorcycle engines) as the phone starts heating up. When she pulls the phone out of her pocket, she can barely hold it because of the heat and it will not turn on at all. When she plugs it in (to the wall charger or car charger) it shows that the battery is at 0% and says that it must charge before it can turn on. Then the screen immediately turns off. The battery had drained from over 75% to 0% in just a few seconds.

Once the phone completely charges, it seems to function normally again. The recharging time didn't seem abnormally long for a battery at )%

Has anyone else had any experiences like this?

We could take it back and get it replaced under warranty, but we don't really didn't want to go through all of the effort of setting everything back up and installing all of the apps again.
Other than this one issue, the phone has been fantastic.

The phone is a totally stock Pantech Burst running Android v2.3.5 as purchased. It is not rooted or modified at all.