shelly 1 with add-on and magnetic contact not reporting external switch change

Hi All

I have a new shelly 1 with latest firmware as of today 25th August 2021. The device is working well as expected with 220v

However I have installed a temperature add-on with an NC magnet contact wired to yellow and black wires. External switch option is enabled in the shelly 1

However even if I short manually the yellow and black wires, nothing happens in the external switch status and no open or close status change is reported. The external switch is always reported as open mqtt enabled shows shellies/shelly1-40F52XXXXXX/ext_switch/0=0

Is anything I can try to check this behavior?

Thx!!