I would check the pop bumper driver boards. The actuator switch can be stuck closed and the driver board is designed to only pop once and not stay locked on.
There is a mod which MUST be done to the driver boards. See pinwiki.com for more info. Also the header pins need to be reflowed and you should add some solder around the hole where the transistor bolts to the board. This will help with unusual behavior and blown fuses.