Two switch light control

[wdc202]

A curiosity I can’t understand. Can anyone explain what’s going on here?

I have a light controlled by a normal two switch arrangement (I can turn the light ON or OFF from either of the two switches). Works fine 99.9% of the time. But every now and then (maybe twice a year), I find that one of the switches fails -- snapping it (many times) has no effect. But if I snap the other switch, just once, then everything returns to normal and both switches work fine again. A puzzlement.

[jnaas2]

One of the switches is failing to make contact, if you replace the switch the problem should be solved

[HayZee518]

the three way switch makes and breaks one of the travelers which connects the two switches together. like jnaas says one of the internal flop-overs isn't making up all the time.