Lovelace: Cards missing certain elements

Configuration Frontend
1

On certain devices (Fire Tablet, Ubuntu in VirtualBox) certain elements of a card are missing:

Bildschirmfoto von 2020-10-28 15-18-51
Bildschirmfoto von 2020-10-28 15-18-511765×595 60.3 KB

Interestingly, I do not have any issues on iOS, iPadOS or Windows.
The problem exists in the home assistant app and in any browser I tried on those devices (Silk, Firefox).

I run 116.4.

Any idea where to look?

2

Problem persists in 116.5

Interestingly it seems to be limited to custom cards. Standard cards appear to be displayed properly.