I'm sorry if I didn't word that title question correctly. I hope my explanation below is easier to understand.

When I wake up and look at my Unraid dashboard, I expect at least one notification from "Mover Tuning" saying whether it did or did not transfer any data to the array. The notification for that is just a green circle with a check mark in it. If I haven't deleted or archived past notification though, and there is something with a yellow triangle exclamation from days ago, like say a high cache disk usage, or something from "Fix Common Problems," then the icon will be the yellow triangle, even if those notification were from days ago and I've already seen them. It seems to me that if just clicking the bell to see the notification is enough to reset the bell icon back to the default, then the system has acknowledged that I've see the notification there, and it shouldn't be showing me an indicator for notification from days ago that I've already seen, it should just be whatever has happened since I last clicked the bell.

Is there a setting somewhere that change this, or is this a feature request I should submit? Or is this something that is already in the pipeline and I'll just have to wait a bit?

Your title is clear. This is how the bell currently works, and there's no setting to change it.

The icon shows the highest severity of all your unread notifications, not only the new ones. Opening the bell hides the icon until another notification arrives, but it doesn't mark anything as read. When the next Mover Tuning notification comes in, the bell shows the highest level still in your unread list. If an older warning is still there, you get the yellow triangle.

To avoid this, archive notifications after you've read them, either one at a time or with Archive All in the Unread tab. Archived notifications don't affect the bell. After that, a new normal notification only shows the green dot. If some warnings keep coming back, for example cache usage, it can help to adjust their thresholds or fix the cause.

A bell that only shows the severity of notifications newer than when you last opened it is a reasonable idea. You can submit it as a feature request at https://product.unraid.net.