If you call MapDynamic for a value where a string should be converted to a Guid?, you get a System.Exception : Invalid cast from 'System.String' to 'System.Guid'. I looked through the code and the GuidConverter's CanConvert method indeed does not check for nullable Guids.
Also in ConvertValuesTypeToMembersType you should probably check if the member type is nullable with the same underlying type as the valu, so you don't try to convert a Guid to a Guid? for example.
If you call MapDynamic for a value where a string should be converted to a Guid?, you get a
System.Exception : Invalid cast from 'System.String' to 'System.Guid'.
I looked through the code and the GuidConverter's CanConvert method indeed does not check for nullable Guids.