Synthesizer settings repeated multiple times in the .mscx file

Hi,

every time I save my .mscx file, the synthesizer settings get appended to the ones in the file, so after a few saves, it looks like this:

<Synthesizer>
<master>...</master>
<Fluid>...</Fluid>
<Zerberus/>
<Zita1>...</Zita1>
<master>...</master> <!-- repetition starts here -->
<Fluid>...</Fluid>
<Zerberus/>
<Zita1>...</Zita1>
<master>...</master> <!-- once for each time I saved the score -->
<Fluid>...</Fluid>
<Zerberus/>
<Zita1>...</Zita1>
</Synthesizer>

This duplication looks unnecessary and can probably be fixed.