Home App camera thumbnails not working on IOS (iPad, iPhone) but work on MacBook

The Home App camera thumbnails on my MacBook are updating fine, but on the iPhone and iPad they're stuck.

If I select a camera on iPhone / iPad streaming video works fine, and seems to kick the thumbnail updates into working.

But closing the Home App and opening it again, the images are then blank until selected when they'll display again, but still won't update.

This worked fine yesterday.