https://qt-project.atlassian.net/browse/QTBUG-149431
https://bugs.kde.org/show_bug.cgi?id=524657
https://mail.kde.org/pipermail/distributions/2026-August/001726.html
--- a/src/gui/image/qiconloader.cpp
+++ b/src/gui/image/qiconloader.cpp
@@ -152,6 +152,5 @@
 
     if (m_systemTheme.isEmpty()) {
-        const QString &themeName = systemThemeName();
-        m_systemTheme = !themeName.isEmpty() ? themeName : fallbackThemeName();
+        m_systemTheme = systemThemeName();
     }
     return m_systemTheme;