I confirm the OP’s problem for Meta and my own Discourse too.
Here are screenshots from my Gmail and Mail app on MacOS and iPhone respectively.
Below are details for my own Discourse forum after ./launcher rebuild app
Don’t know if other can see the e ail logo for meta. I would like to know of that’s on my end only.
I did a ./launcher rebuild app yesterday.
The issue has been fixed in today’s update:
https://github.com/discourse/discourse/commit/27c793a192ea0443373dc65517b50dfa21480441