I’m running the stock theme, stock everything. I don’t have another phone otherwise I’d try it there, of course, to see if it is just me. Although, this was the same when I had an S22 Ultra too.
eta: found a solution for Samsung owners using the stock UI. You can use the Theme Park module within Good Lock to create a custom icon pack. What I had to do was set the icon shape to none (the dashed circle) for all icons, upload the Discourse icon with a transparent background and set that as the app icon.
Looks like your launcher is going a bit overboard and clipping a bit more than the “Minimum safe area” for maskable icons .
We mark PWA icons as Maskable by default, so they are allowed to be cropped by each launcher in order to not litter the homescreen with white background around the icons.
The trade-off is that you don’t have complete control over the final look, as it will be slightly differently cropped in every launcher.
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. On my Samsung (A14), I see it like Falco. Glad you found a workaround, though!