How to return the Joomla menu after the update?

Question

Joomla

Joomla was updated from version 3.3.0 to version 3.9.14
Apparently, because of the update, the menus were lost, that is, it was like this:

but it became like this:


Although nothing has moved out on the site itself, everything is displayed correctly.

Answer 1

1. Restore from a backup on a test lab and update again.
2. Solve the problem there and backup.
3. Deploy a new backup to production.