Hello, when disable the locked background, it’s work.
I’ll take a look at a possible fix for this. It will likely end up being the same solution as the Banner stack wherein it becomes a non-locked image on mobile devices, as the devices do not provide good support for locked backgrounds natively.
And what about the background in Foundry, you see it on page vb2
The image is set to cover the entirety of the site background. Since the site background is now much longer on the mobile device it is being upscaled to cover the entire background.