User is already being used error

[noctivityinc]

Trying to run a method we've run 1000 times:

response = DRIP_CLIENT.create_or_update_subscriber(subscriber_email, options)

but are now getting this odd error:

#<Drip::Response:0x00007fa0bb3d6540 @status=422, @body={"errors"=>[{"code"=>"uniqueness_error", "attribute"=>"user_id", "message"=>"User is already being used"}]}, @links=nil, @meta=nil, @members={"errors"=>[{"code"=>"uniqueness_error", "attribute"=>"user_id", "message"=>"User is already being used"}]}>

Is the API having issues?