MS Graph .net SDK cannot expand calendar event SingleValueExtendedProperties

Question

I need to read a certain SingleValueExtendedProperty from a calendar event.

I'm already doing that in a Teams Tab app and in the Graph explorer webpage, but somehow I can't using the ms graph sdk for .net.

Reading the documentation I need to expand the SingleValueExtendedProperties property filtering by id.

string idTest = "String {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} Name nameofproperty";

Event result = await _graphServiceClient.Users[email].Events[eventId].Request()
                                                                     .Expand($"singleValueExtendedProperties($filter=id eq '{idTest}')")
                                                                     .GetAsync();