I have a workflow that is sending a workflow for people that attend a meeting which the meeting holder input the attendees in a Nintex Form and then the workflow sends meeting notes to the attendees. Part of the workflow is to loop through the attendees and query the user profile service for finding all users First and Last names. 

I am finding an issue with this action in the workflow. For some reason some users cannot find the user profile for some users. I find if I add the user to a separate list this seems to resolve the profile there after. However, today I was looking into the details of a workflow that was giving this error about no user found and looking behind the scenes at the userInfo list the user was listed in the list. 

I am not sure how to resolve this issue. I am syncing our complete AD forest daily. We starting syncing all of the other subdomain since we were only syncing one subdomain previously. I thought this change would have resolved this issue however, I am getting these issues list above.

Does anyone have this same issue or know why this is happening? The list ID of the user that was complaining was 5396 and the last user in the userInfo list is 7625.