Custom data attributes not accessible

hi,

it's AEM 6.5

I'm extending Carousel component, I added some custom data fields passing configuration data from cq:dialog.

AEM data layer is not enabled (I tried to enable it but same result)

What I experience that only oob Carousel data are accessible, like data-cmp-autoplay  and data-cmp-delay but my custom data attributes are stripped.

Thank you