Hi! I can make a test site maybe with test url, because that site already works in live in other domain and I can't update because that errors.
There are no custom positions, I just make different raws with addons (simple image and text), and I set one of them to hidden on desktop and tablet, and the other one to hidden on mobile. So I make different raws with almost the same content because of the devices to appear or not. It's a simple thing, I use this method all of my sites for years with helix and Sp Page Builder. So I make nothing special, it should be works well regardless version number.
But as I saw in your blog, maybe the new raw's hidden functions causes this error/bug - but it's a big fault, because we (website makers) cant set again in all pages our raws hidden function for devices - just in one page I usually have 20-30 pages...