CRM 2016, JavaScript, using soap to RetrieveEntityMetadata of an entity with new Customer type (new_mycustomer) returns 500 (Found an integer attribute with unrecognised format: new_mycustomeridtype)

Hi,

CRM 2016 Sp1, I am using XrmServiceToolkit to RetrieveEntityMetadata for a custom entity which includes the new Customer field (my_customer). The function returns with the status 500 and error message:

Found an integer attribute with unrecognised format: new_mycustomeridtype

The same code works for any other entity as long as it does not contain the new Customer field.

Using new Web API works without any issues.

Is this a bug or do I need to make any changes?

Note: I have to use soap as the product I work on need to be compatible with 2013, 2015, and 2016

Thank you for any assistance,

Mehrdad