Comment by danbruc
This article [1] has an image of the pager and a video supposedly showing one exploding in the bag of some guy while shopping groceries. From that I would suspect a supply chain attack integrating some explosive, that seems way too violent for just an exploding battery or anything else you would usually find in that kind of device.
[1] https://realrepublic.com/encrypted-hezbollah-pagers-simultan...