API: Roles not saved on POST /api/User. “Performer” role missing on bulk-created users (~20,000)

I have discovered another bug that it is major for us. Our Performers portal is secured by a Role of "Performer". I tried to use the API to mass create the users for the portal (we have about 20000) however the Role is not attached to the user when created by API

Posted this to /api/User: {
"$type": "Asi.Soa.Membership.DataContracts.UserData, Asi.Contracts",
"IsDisable": false,
"Roles": {
"$type": "System.Collections.ObjectModel.Collection`1[[System.String, mscorlib]], mscorlib",
"$values": [
"Performer"
]
},
"IsAnonymous": false,
"UserId": "839403",
"UserName": "04-25932",
"Party": {
"$type": "Asi.Soa.Membership.DataContracts.PartySummaryData, Asi.Contracts",
"PartyId": "839403"
}
}

the response does include the Role correctly, however if I go to the user on the staff website, the role is not there, if I do a get for the same user the role is missing as well.
I need a solution to this yesterday. Do you guys have a way to mass add roles to users?