Graphical issue iPad version

I would like to report a small graphical issue with the Notation toolbox:

I am working in split view (2 Apps next to each other):

At this point I would like to input a double bar line.
In the Notations toolbox I have activated Panels Panels button
If I click the bar line tool, I will get a black space (and nothing to choose from…).
All other tools will just show the black space:

Still, I can keep on working by switching and activating Popovers Popovers button
From here I can choose the bar line popover and input the double bar line via || keyboard.
The application does not crash, it is just this black empty space showing, Dorico isn’t happy about something. Could it be the iOS split view?
This happens only from time to time, not always. At the moment the Panels are working again - on the same file, which is stored on iCloud and which I have actively open on my iPad since yesterday.