When rendering Labels, Billboards, and Map Pins in CesiumJS on a Raspberry Pi 5 running Raspberry PI OS 64-bit with the latest Chromium browser, a black rectangle appears behind the text or icons.

In this app, the layers of the foreground and background shift as I tilt my phone, creating a pleasing parallax effect. If I don’t move my phone at all, the background is sometimes completely still, ...