Email is always null for several Graph API Team endpoints

Question

When I run https://graph.microsoft.com/v1.0/me/chats?$expand=members, I'm consistently getting email: null for all of of my chat members. Why is this happening? The only workaround I have is to get the chats individually.

Another update: I see this issue on several endpoints:
* https://graph.microsoft.com/v1.0/me/chats?$expand=members
* https://graph.microsoft.com/v1.0/teams/{team id}/channels
* Shows up as empty string
* https://graph.microsoft.com/v1.0/teams/{team id}/members

This isn't an exhaustive list. These are just the endpoints I've found.