Shelly dimmer 2 doesn't calibrate correctly

[Fabio Frye]

 

I'm using a Shelly dimmer 2 with neutral wire and no bypass and one Philips GU10 3.8w LED Warm glow.

As you can see in the video, the brightness increases linearly from 0% to 90%, it goes from 0lux to 320lux. Then from 90% to 91% it goes from 320lux to 830lux in 1 minute (sometimes less).

Also when lowering from 87% to 86% it goes from 790lux to 280lux in 10 seconds.