Content Search API - Filter buy ContentReference/ExpandedValue

Hello!

We are trying to search by content type TeaserBlock and it's property VisitorGroupBlock's (which is of type ContentReference) expandedValue (block of type VisitorGroupBlock).

An example query:

/api/episerver/v2.0/search/content/?filter=ContentType/any(t:t eq 'TeaserBlock') and visitorGroupBlock/expandedValue/recommendationCategories/value eq '88180247' 

ERROR EPiServer.ContentApi.Search.Internal.FilterHelper: Fail to build lamda expression
System.ArgumentException: Property 'visitorGroupBlock' is not defined for type 'EPiServer.ContentApi.Core.Serialization.Models.ContentApiModel'
at System.Linq.Expressions.Expression.Property(Expression expression, Type type, String propertyName)
at EPiServer.ContentApi.Search.Internal.FilterHelper.GetPropertyNameAsLambdaExpression(Type type, String dotNotation)

Can someone point out what we are doing wrong? :)