I have this odd issue. It happens on Chrome on the desktop, on mobile, and in the HA companion app (on Android at least).
Sometimes when I go to one of my custom dashboards that has tabs, only the first tab shows, and none of the others. It does the same when editing. I've included a couple screenshots of what it looks like when I go to edit on the desktop, and some screenshots of what viewing looks like on the HA Companion app.
I've tried using the developer tools in Chrome to see if it wasn't downloading something properly, and the payloads all look the same when it works and when it doesn't.
Sometimes it works, sometimes it doesn't. It always seems to work when I refresh on desktop, but there's no real way to refresh the same way on the companion app.
I've even tried re-installing HA completely on another box just to test it, and it does it there too. I'm not sure if anybody else has seen this, or knows of any ideas to try to track this down. It's just.... weird.