The spinning ball animation showing application start is in progress for long starting applications stops too early for many Qt/QML applications. This is visible e.g. in qmlgallery (Qt Quick Components gallery). In some applications I saw it is not happening every time (normally so that first time when starting the app the animation stops too early but later launch it shows longer).
Ensure you have them effects on from Theme settings (Settings->Themes->General themes->(Options menu)
>Theme effects>On). Also ensure no test images is flashed as these have configured effects off (even if the settings say they are on).