Can't say I have ever had any issues with leaf tampers other than the fact they are easier to smash the lid off on JB's, relying on the one central screw.
The more common issue I see are with these type are wiring not wrapped around the screw correctly or snapped or loose resistor lags making intermittent contact
It's not mandatory to have switches but most have gone that way as it's easier to manufacture a break out back tamper. You also have the benefit of not seeing the faults above.
I also wonder what brand and did you find any evidence to suggest it was the leaf at fault?
For the cost of the device if your suspicious of it, may as well be replaced as part of whatever diagnosis you are doing, you have been called out anyway