If you create a navigation level greater than two, the navigation doesn't pop out the third level correctly.

Instead it simply widens the menu and adds scrollbars.

To recreate this bug
Check out MOODLE 26 Stable

Fresh install + change to clean theme.

Go to theme settings and add some navigation headers, out to 3 or more levels
Moodle COMM|
-Moodle comm|
--Moodle comm|
---Moodle comm|

Save and verify that the navigation headers do not behave as expected.

I originally spoke with Julian Ridden about this as I assumed it was a bug with the essential theme, however he pointed out it was actually a bug with the bootstrap base theme and all themes that inherit from it.

Here is the discussion https://github.com/moodleman/moodle-theme_essential/issues/84

Some screenshot are visible on the github discussion and I will attach them here as well.