How to select switch type sent to google home?

In my dining room, i have 2 Lutron dimmers and a group of 2 zigbee plugs, the 2 zigbees are listed as a group "ambiance"

I started with 1 dimmer and the "ambiance" group, surprisingly, they both appear as "lights" in the Google app, with dimming, color selection etc...
I added a new Lutron dimmer yesterday (identical to the first one ) and this one appears as a switch in the Google app !
I don't understand
Can anyone enlighten me on why 2 identical dimmers appear differently in the Google app ?
Thanks !