I just created a customer list, and added an email column. I noticed that a number of users don't have their email address listed, but when I opened each user's profile page I can clearly see an email address in it. Why can't I see it in my customer list?
If you have Google Sign-in enabled for your end-users under Admin > Settings > Security > End-users, there is a distinction made between Google email identities and other email identities, and there is a separate column for Google email identities. Please add Google as a column in your customer list to see these users' email addresses. This behavior is intentional, and meant to make a distinction between Google identities and email identities.