As the notification percentage (of downloads and/or indexing) changes, the notification popup jumps back to the top of its content. This is very distracting to lose your place as you're trying to view what's new/updated.
You don't even have to be actively scrolling for this repositioning to happen. Just scroll down a bit and wait, and the content will suddenly scroll back to the top to show you an updated (downloading or indexing) percentage.
8.3 SR-3 (8.3.0.0034) on macOS 10.14.3 (18D109)
