Because the setting you showed applies to GNOME Shell, not Budgie.

When a user says to "turn off notification pop-ups", they would rightly expect that to mean all notification pop-ups, not just some of them. Isn't solus the only project that has any control over improving how that setting works? It seems like a legitimate issue but was closed as invalid.. should I submit a separate task just for that issue? I don't personally care if it's fixed as I prefer to have pop-ups turned on, I was just trying to shut Firefox up and noticed it. It seemed worth reporting

Lastly, where would you suggest I go to report the issue about notifications popping up on top of full-screen games? Is that a budgie thing? I'm not terribly familiar with the internal workings of that stuff.

Thanks

should I submit a separate task just for that issue

No you should submit it in the right location. This isn't just a Solus issue, it's the fact we utilize GNOME Control Center for GNOME *and* Budgie, where Budgie doesn't utilize the GNOME Shell specific settings exposed in GNOME Control Center. As such, it's a Budgie issue, and thus should be reported to the right place.

Lastly, where would you suggest I go to report the issue about notifications popping up on top of full-screen games? Is that a budgie thing?

Correct.

OK, will do. Some of these things are hard to pinpoint what project is responsible for those of us who don't write the code.. thanks for pointing me in the right direction

No problem =)