MongoDB oData support

I am using MongoDB c# driver 2.10 together with core data 7.2.
however when I am trying to use the Query Option $apply like
I got the exception of 'Value type of serializer is System.String and does not match member type System.Object.

After digging deeper, I found MongoDriver’s PipelineBinder is trying to bind a object of below:

.New Microsoft.AspNet.OData.Query.Expressions.GroupByWrapper(){
    GroupByContainer = .New Microsoft.AspNet.OData.Query.Expressions.AggregationPropertyContainer+LastInChain(){
        Name = "path",
        Value = $$it.Path

But this object is not a simple property of my entity, so the driver failed to bind it.
Is it a bug in MongoDriver supporting oData expression?