Zigbee Light switch - backlighting works, but button doesn't

I have an OXT brand light controller/switch using Zigbee. It supposedly supports backlighted buttons, the integration allows to set backlight modes for example.

Tried to use a typical 230V monostable button with backlight, and while the backlight works just fine - the switch doesn’t do anything. Tested it with multimeter, and seem to work just fine - over the scale resistance when not pushed (I assume the backlight goes trough some very high resistor?), and zero when pushed. Shorted the trigger wires of the controller manually and it also works, so the controller works just fine.

And yet, the two together are a no-go. Do you guys seen anything like that?
Maybe I should change something in the zigbee config of the controller?
Switch type is already set to momentary button.

As it states in the pinned post, what is exported by the individual coordinator software or device is best asked in the home site of your controller software. (Z2m, ZHA, Decons, etc.) You need to contact those contributors for help with those.
Someone here might know, but to fix it you need to be there.