I think this is a (minor) bug I noticed just now.

A post with the green megaphone from a sub that I subscribe to was showing up in All just now evening though I have the option turned on to hide subscribed in All/Local.

Specifically this is the post in question:

https://sopuli.xyz/post/10540905

Edit: on further thought, I’m not sure if the announcement part matters since I see other subs with that green megaphone in my Home feed and not in All. Sorry this is a terrible bug report.