In all of this, all I can think of is a recent automotive issue I had. Well, it was a mechanical/electrical part malfunction.
In my car, the trunk latch is a mix of a mechanical latch that is controlled with electrical signals. The mechanical arm failed, and it could have been because of a short from the electrical signal melted/weakened some of the plastic inside of the device, and the latch wouldn't swing into the unlock position despite unlocking it with the key, or with the electrical signals.
Yes, even now, parts are often made with a mix of metal, plastic, and ceramics. So it shouldn't be beyond imagination that a stray electrical signal sent into a device could cause a spike in the heat, which causes it to structurally weaken some of the plastic/metal components. Or maybe a rogue electrical signal causes a vibration which causes micro-fractures in the ceramics, which then it to catastrophically fail at a key time.
In a weapon, the electronic area of the weapon is probably as far away as physically possible from the mechanical components, but it's still contained in a device, there are still linkages where things can go wrong. We have weapons now where the trigger does not activate a hammer, that then swings forward and strikes the ignition plate on a cartridge of ammunition. Instead, the trigger sends an electrical signal which travels and ignites a block of ignition material which then propels the bullet away from the caseless ammunition propellant. So, a Hacker sending signals to fry the innards of those weapons can totally keep the weapon from working.
As for a cased weapon that is still wireless, it could be an overloaded signal that generates such heat in a small area, that it just causes structural harm to the mechanical parts. Warps and weakenes the metal, or melts plastic, etc. Yes, the weapon is designed to withstand the shock and temps of firing in certain locations of the weapon (mainly the firing chamber/barrel), but structural weakening in other areas can do their share of damage to the weapon