KnockoutJS Mapping Plugin skips "create" mapping
===

I'm having an issue where the mapping plugin doesn't seem to acknowledge that there is a create function in the mapping. I wish I could share more code, but per my employer, that is impossible.

Basically I am calling the mapping with something like: 
  

       
    var _mergeHistoryMapping = {
      key: function (data) {
        return ko.utils.unwrapObservable(data.TouchIDString);
      },
      create: function (options) {               
        return new _model.mergeHistory(options.data);
      }
    };
    
    ko.mapping.fromJS(data.Touches, _mergeHistoryMapping, self.touchHistory);

It runs the key function every time and appears to add the key to the KO mapping key collection just fine...however the create is never called. 

data.Touches is a JavaScript object with no nested arrays. Even when I step into the KO mapping plugin code it acknowledges hasCreateCallback() == true. It looks like it is going to call createCallback(), but then it just never reaches back out to my code.

Does anyone have any ideas as to what would cause the mapping plugin to do this? I'm mapping things all over my code with plenty of success...it's just this one specific instance that isn't working. 

Thanks in advance...sorry for the lack of example code :(