The screenshot was taken from Firefox on desktop, running the latest version 1.5.0. The badge is a prompt to install.
The same issue occurs on iPhone PWA 1.5.0, iPadOS PWA 1.5.0 and native application 1.5.0.
I have updated the original post with this info.
Didn't occur to me until your comment to view the post outside of Voyager, and I also see only four replies to your post at https://sh.itjust.works/post/2352604
Must be a bug then. Thanks all :)