Email labels ('+' sign) in alternate key not working

[rfontijn]

I use an email address field as part of an alternate key on the contact entity.

However, when using upsert using Webapi (PATCH), or retrieve (GET) using this key when there is a Gmail label in the emailaddress, I get a 404.

So basically this doesn't work: ruben.fontijn+microsoft@gmail.com

Example request: 

curl --location --request GET 'https://company.crm4.dynamics.com/api/data/v9.2/contacts(hso_label=864640001,emailaddress1=%27ruben....)' 

404 - File or directory not found.
The resource you are looking for might have been removed, had its name changed, or is temporarily unavailable.

See also my documentation issue request:

https://github.com/MicrosoftDocs/dynamics-365-customer-engagement/issues/2697