I noticed that when I dismissed my popover the text was changing its style...
SwiftUI 2 popovers don't properly update if one was already displayed and you trigger another.
While working on the iPad UI variant for our iPhone video subtitles app Captionista, I noticed that when swiping to dismiss in compact horizontal size class or on iPhone, the popover transition freaks out — as recently as iOS 14.1 and SwiftUI 2.
Popovers in SwiftUI don't provide a way to change the colour of their arrow, and if you do not use a NavigationView but set a custom background colour, you will be sad that the arrow looks terrible.
The initialisers of Views in SwiftUI have some surprising and obscure behaviours related to state. If you've used SwiftUI at all you will likely have discovered this. In addition, the rules around how properties that are wrapped with Property Wrappers are accessed are interesting when inside the initialiser of the type. It is this latter issue that bit me.