Why relay contact stick even when power off?

[hevans1944]

It's also possible to help snub the circuit if you can alter (reprogram) the output logic.

That would be a nice solution perhaps, but this is likely a commercial product with "programming" built in and modifications not supported by the manufacturer. Always fun to try hacking such things to "improve" their performance and/or reliability.

 

[Bluejets]

The little blue varistor is a nice addition. Too bad though that no component values are given. Guess you buy it and try it, and for less than two bux maybe that's a bargain... sure can't build it for that price. Good find @Bluejets!

220R
630V 104 cap
mov 10D471K