OSX: Wrong theme icons are loaded when app is deployed with macdeployqt

[pbe]

I'm using custom icon themes for QOwnNotes.
In dark mode I set a theme breeze-dark-qownnotes with QIcon::setThemeName("breeze-dark-qownnotes").
Here is the icon resource file: breeze-dark-qownnotes.qrc

That works perfectly under Linux and Windows.

When I build with qmake under OS X it still works perfectly. But when I use macdeployqt QOwnNotes.app to finally deploy the app the icons from the dark mode theme are not used anymore. Instead the icons from the default icon set breeze-qownnotes are viewed in the toolbar and everywhere else.
Here is the default icon resource file: breeze-qownnotes.qrc

Does anyone have an idea what went wrong?

I tested with Qt 5.5.1 on OS X 10.11 and on Travis Ci, also with Qt 5.5.1.
QOwnNotes OS X build on Travis CI, this is where the release building is done.

[pbe]

I now filed a bug https://bugreports.qt.io/browse/QTBUG-54960.