See my post on Shelly EM
it looks like there is a serious bug in the latest firmware
You can not set the relay on either the EM or shelly1 , on both it doesn't matter what seeting are used on the web gui
as soon as you set the relay state, withing 20 seconds it reverts to the slected state of the button on the embedded web gui.
I now have 4 shelly1 switches that are useless, and a EM which the contactor control cant be used.
Luckily I used a SONOFF with Tasmota s/w to do some of the switching, but the other part of my application is useless.
On both you can watch the relay state with MQTT Explorer , change state as selected , then within 20 seconds it reverts to
the state of the embedded web gui button
I am extremely miffed over this !!!!
Please sort out your firmware , this is a serious bug