E1 Menu in an E1 Page does not render - can anyone tell me why/how to fix?

I have created multiple E1 pages with E1 menus added to them. When testing, we experienced rendering issues with the menu section of the E1 page. There is an icon and message displayed which says "The menu is in the process of being rebuilt. Your content will load shortly. You should be able to perform most tasks within the system while you wait."

I found documentation on the P90013 and the 'Build by Task View'. This corrected the problem for most users, however we are still having the issue for some users. For some, it is working fine in the PY environment but not in PD and for others not in PY but OK in PD.