SVG output with STIX & fonstyle italic => overlap

The following example has some unwanted overlap at 2x-3 in the numerator. THis is using STIX fonts in SVG output.

    <math xmlns="http://www.w3.org/1998/Math/MathML">
      <mfrac> 
          <mstyle fontstyle="italic"> 
            <msqrt> 
              <mn>2</mn> 
              <mi>x</mi> 
              <mo>-</mo> 
              <mn>3</mn> 
            </msqrt> 
          </mstyle> 
          <mstyle fontweight="bold"> 
            <msqrt> 
              <mrow> 
                <mn>3</mn> 
                <mi>x</mi> 
              </mrow> 
            </msqrt> 
          </mstyle> 
        </mfrac>   
       </math>