Wrong delay for sub menu to open when already other sub menus were opened

Background: when hovering over a menu item that contains a (sub) menu it takes a certain time until this opens. This delay can be increased and decreased at least in both Windows and Linux/X11. You might have to set the delay to a higher value to make the bug stand out more. Here is explained how one can set this delay higher directly in the Qt source:

https://bugreports.qt.io/browse/QTBUG-53054?focusedCommentId=318717&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-318717

Steps to reproduce:

1. Open a menu with menu items that open sub menus (like in the app attached).
2. Go one menu item and open the sub menu.
3. Move back and forth between other menu items that contain sub menus.

Actual behavior:

• A sub menu is opened by hovering even if the delay per menu item did not pass.

Expected behavior:

• A sub menu should open only when the mouse pointer is over it for the defined delay.

I have also attached a screen capture that should illustrate the problem. Notice how first no sub menu opens when alternating between two sub menus while staying on each item for less than 5 seconds (this is the delay I set). But once a menu is opened other sub menus open even though I does not stay on a menu item for at least 5 seconds.

My hunch is that the timer that is used for closing first opened sub menu after 5 seconds (which is the correct behavior) is also used for opening the next menu (which seems false). But I am not a developer and haven't looked at the sources, so it is just a guess,