On the desktop, it looks as it should when installed both via Firefox and Chrome:
However, the story is different when the icon is shown in the app switcher.
Chrome looks as expected:
But Firefox does not:
Chrome does some extra stuff when installing a web app, seemingly packaging it into an APK or similar and installing it more like a "traditional" Android app, which is likely why they don't run into this problem. Firefox is more direct and lightweight in that respect, but might be running afoul of launcher bugs due to that.
There doesn't seem to be much to be found online about this, but these seem notable:
On the desktop, it looks as it should when installed both via Firefox and Chrome:
However, the story is different when the icon is shown in the app switcher.
Chrome looks as expected:
But Firefox does not:
Chrome does some extra stuff when installing a web app, seemingly packaging it into an APK or similar and installing it more like a "traditional" Android app, which is likely why they don't run into this problem. Firefox is more direct and lightweight in that respect, but might be running afoul of launcher bugs due to that.
There doesn't seem to be much to be found online about this, but these seem notable: