Cannot create contact with custom data in schema extensions, group works - microsoft-graph-api

Question

I have created a schema extension for group and contacts.
First Issue: I can create new group with custom data using the extension but not with contact. I get the following error when I try to create a new contact with custom data in schema extension.
{
"error":
{
"code": "RequestBodyRead",
"message": "The property 'extcivhhslh_sbtest1' does not exist on type 'Microsoft.OutlookServices.Contact'. Make sure to only use property names that are defined by the type or mark the type as open type.",
"innerError":
{
"request-id": "5686a76f-f016-47aa-82a3-acd9ab57e3ae",
"date": "2017-06-14T05:44:22"
}
}
}
Issue#2: As per the 5th example in https://developer.microsoft.com/en-us/graph/docs/concepts/extensibility_schema_groups I should be able to get the custom data in the extensions. In my testing I don't get back the custom data in the extension.
The extension looks like the following:
{
"#odata.context": "https://graph.microsoft.com/v1.0/$metadata#schemaExtensions",
"value": [
{
"id": "extcivhhslh_sbtest1",
"description": "SbGraph test extensions",
"targetTypes": [
"contact",
"group"
],
"status": "Available",
"owner": "da033fe6-d48e-435d-8014-e98a4b166900",
"properties": [
{
"name": "customerType",
"type": "String"
}
]
}
]
}

Answer 1

1 - Schema extensions cannot be used while creating the contact. Once the contact is created, you can patch it using schema extension value.
2 - Please verify that you have specified $select=extcivhhslh_sbtest1 while querying for /groups to get the extension values (along with other $select properties that you are interested in).
Thanks,
Pavan