possibly bug in \fret-diagram

[littleflock]

Greetings ,
I am using \version "2.10.33". I experienced incorrect results 
upon resizing \fret-diagram , specifically for 

\markup
\override #'(size . 3.0){
        \override #'(dot-radius . 0.35){
                \fret-diagram-terse #"x;x;o;2;3;2;"
        }
}

Everything is resized correctly APART from the 'x' and 'o' in the 
argument list of \fret-diagram.
Could please someone have a look at that if time allows ? Ohh, I would 
appreciate an answer  on the outcome. Thatnk you all for this 
incredible software.
Regards, Frank