Did you switch to "simple menu (blazing fast)"? It seems so ...
That setting would NEVER be able to use labels, not in ANY X3 release. Either you changed it now with the new release, or you for some reason just happened to have a cached menu variety before you changed to use "Simple menu". Disable it.
Simple Menu Mode
Simple menu mode will drastically speed up the creation time of your menu. Because of the limitations, this setting is normally unsuitable, but if you have thousands of pages and/or are hosted on a very slow server, it could be a beneficial compromise.
Why so fast?
In simple mode, the menu is created by simply reading the directory structure of your content. Instead of having to load page data for each menu item, it simply creates menu items based on folder names.
Limitations
Simple menu mode has several limitations:
- Does not support mega menu.
- Uses folder name instead of label from page settings -> plugins.
- Does not support special menu settings like links.
* Use this setting if you plan on having thousands of pages and don't require advanced menu behavior. This setting may be especially useful for the sidebar layout.