Data attributes can not have multiple hyphens

Wanting to add Pinterest data-attributes to image tags, the HTML looks like this:

<img data-pin-media="<?=$imageUrl->url()?>" />

But Kirby returns:

<img data-pinmedia="" />

Only the first hyphen comes out!

Has anyone ever had this problem? Is it a Kirby bug?

Thanks for your help

I can’t reproduce this. What Kirby version are you using?

Sorry! In fact, I found the issue. It’s not a Kirby bug. it’s a lazysizes bug (a script to lazyload images).