I am using the following customization for "Refactor Document Method" but I guess it happens with the default one too: some method arguments cause emtpy values. The type Dictionary<String, String> for example causes one emtpy line; or better, any generic with more than one parameter causes one emtpy line for every aditional parameter. Interesstingly it does not happen for the return type.
/// <summary>
///
/// </summary>
/// <param name="$MethodArgName$"></param>
/// <returns>$SymbolType$</returns>
Using Document Method on this:
void FuncX(Dictionary<String, String> paramX){}
Produces:
/// <summary>
///
/// </summary>
/// <param name=""></param>
/// <param name="paramX"></param>
/// <returns>void</returns>
I have seen cases where instead of the parameters name, the type + name appear. But i cant repro it reliably, seems to be related to newly created classes.