Hi Gail, sorry for the delay
Can you confirm you have checked the 'Roles that are not synchronised' option in Site administration ▶ Plugins ▶ Enrolments ▶ Course meta link
The only way I'm able to replicate having users with no role is to have the role selected in that option. I have found I need to remove the linked course and add it again after changing the 'Roles that are not synchronised' option so you might need to remove the linked courses fix that setting then add them again.
Unfortunately the default for 'Roles that are not synchronised' option is 'None' but once you've selected one role there is no 'un-select' option so I've resorted to selecting 'Guest' as the role least likely to affect my development site
Cheers & I hope this helps
Teresa