Battery problems with THR10

While being used on battery power, the amp would randomly shutoff. After turning the switch off and on, it would work fine for around 10 min then again randomly shut. Rinse and repeat. Keep in mind the amp plays without issue when plugged in. I figured the batteries must be dead, so I replaced them with fresh AAs. Played fine for around 5 min, then I heard a loud pop and a bubbling sound. One of the batteries had exploded, so I immediately removed the batteries and safely cleaned the mess. Now I am scared to even turn the amp back on. Has anyone else had battery issues like this before? Could the battery have been the issue and not the amp? Any advice would be greatly appreciated!