Broken as of FP June Update?

I use a question mark, because I may have caused my own problem on this one....but I am getting the following

Error while compiling MagicDescription: 'StringView' does not contain a definition for 'ToLower' and no accessible extension method 'ToLower' accepting a first argument of type 'StringView' could be found (are you missing a using directive or an assembly reference?) | Line: 198, Pos: 40

replase Line: 198
switch (arg.FullString.ToLower())
-->
switch (arg.FullString.ToString().ToLower())