I used to find that the crystal filters used in certain VHF radios would fail after as few as a couple of hundred hours if they were mounted a certain way in certain machines. I always assumed that it was down to some particular vibration frequency from the engine coupling through the cab.

Although that was nothing to the amount of 0.1μF SMD ceramic capacitors that would go leaky in the same product, and cause all sorts of bizarre faults like drastic loss of sensitivity (decoupling capacitor in IF amp bias circuit pulling down the bias rail) or sensitivity being okay but radio not going into service because the squelch would never open on the control channel (decoupling capacitor in the squelch threshold circuit pulling down a different bias rail).

Bloody things. Fine when they worked, not too horrible to work on when they didn't, at least.

Did they ever fail short?