Microsoft Graph - Retrieving invalid contact email address - microsoft-graph-api

Question

If an Office 365 contact's email address is invalid (ex: user#example?com), how do I retrieve the the email address with Microsoft Graph?
I've tried /contacts and /contacts/{id}. The first returns an empty address:
"emailAddresses": [
{
"name": "name",
"address": ""
}
]
and the second simply omits it:
"emailAddresses": [
{
"name": "name"
}
]
Edit: By "contact" I mean Outlook contacts accessible in the Office 365 People app, not regular Office 365 users. Sorry if my question was unclear.

Answer 1

I'm not sure if this would work, but perhaps give it a try.
string email = await graphClient.Users[your_users_id].Request().Select("Mail").GetAsync().Mail;
To get the answer above, I used this Get User documentation which briefly talks about Select statements. And this documentation has a list of the properties which are available to the Select statement.

Answer 2

Found an issue on Github that solved my problem.
Turns out an Exchange contact's (first) EmailAddress has an hidden PidLidEmail1OriginalDisplayName in addition to its address.
When you set the email address to an invalid one, the invalid address is stored in the OriginalDisplayName and its address is cleared, which is the reason the contact's email address is (Empty) in Office 365 People's contact list but the invalid address seems to still be there when you edit the contact.
PidLidEmail1OriginalDisplayName is an MAPI property. In order to obtain it, we need to use extended properties. The request should look like below but with the spaces URL-encoded to %20:
GET /me/contacts/{id}?$expand=singleValueExtendedProperties($filter=id eq 'String {00062004-0000-0000-C000-000000000046} Id 0x8084')
The response should include an additional field containing the invalid address:
"singleValueExtendedProperties": [
{
"id": "String {00062004-0000-0000-c000-000000000046} Id 0x8084",
"value": "user#example?com"
}
If the contact has multiple email addresses, use PidLidEmail2OriginalDisplayName/PidLidEmail3OriginalDisplayName for the contact's second or third email address.