I don't really like this workaround. I prefer finding out why m_ui->actionQuit doesn't work and fixing that.
Maybe is the Icon (line 188) that cause this problem? Can you test it after removing this line?

If there are no alternative I will accept this

@TheZ3ro it still doesn't work if I remove the icon, but when I remove the setMenuRole() at line 189 it works.

According to Qt docs the menu role can only be changed before the action is added to the menu bar so I don't think there's a way to reuse m_ui->actionQuit, even if I set it to QAction::NoRole when adding to the tray icon menu.

Why don't you set the MenuRole inside a #ifdef Q_OS_MAC and use m_ui->actionQuit in the tray icon?

I mean, adding the #ifdef before line 188

Only macOS uses the MenuRole and this problem only happens on macOS so it would still get the MenuRole anyway.

The workaround only duplicates the quit action on macOS, other OSes still use m_ui->actionQuit at the tray icon menu.

I agree the workaround is ugly but I don't think there's a way to reuse m_ui->actionQuit at OSX :/

Sorry, I was meaning something like:

diff --git a/src/gui/MainWindow.cpp b/src/gui/MainWindow.cpp
index 6a41173..43f6cf1 100644
--- a/src/gui/MainWindow.cpp
+++ b/src/gui/MainWindow.cpp
@@ -186,7 +186,9 @@ MainWindow::MainWindow()
     m_ui->actionChangeMasterKey->setIcon(filePath()->icon("actions", "database-change-key", false));
     m_ui->actionLockDatabases->setIcon(filePath()->icon("actions", "document-encrypt", false));
     m_ui->actionQuit->setIcon(filePath()->icon("actions", "application-exit"));
+#ifndef Q_OS_MAC
     m_ui->actionQuit->setMenuRole(QAction::QuitRole);
+#endif
 
     m_ui->actionEntryNew->setIcon(filePath()->icon("actions", "entry-new", false));
     m_ui->actionEntryClone->setIcon(filePath()->icon("actions", "entry-clone", false));

And using m_ui->actionQuit, that should work

That would work, but setMenuRole() is only useful (and required) at mac and not having it set breaks the quit menu on other languages:
#482 and #430 (comment)

Ok, I was missing those Issues. So I think I can accept this