Cayenne Esp12-e actuator RELAY misbehaving

Esp12-e remote,
Android app and PC HTML

I installed Cayenne on an Esp12-e, with actuator “relay” on GPIO 4

The problem is- the relay drops after about 90 seconds, whether I keep the app active or not.
As if the button signal was a 90 second 1-shot.
Problem is repeatable.
When the relay turns off, it accurately reflects on the indicator HTML or Android app.

Wifi signal is perfect, power supply is clean-

I noticed that this problem disappeared when I used actuator “Generic”, rather than use the actuator “Relay”.

-Just an observation.