I have tagging selected on the plugin. The thing is, tag changes are being made to the actual wav and aif files. But in addition, the xml file created at the same time the tags are updated. The xml file only has one item:
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<MPL Version="2.0" Title="JRSidecar" PathSeparator="\">
<Item>
<Field Name="Filename">M:\CD MUSIC\Stravinsky, Igor\Petrouchka\01 - Petrouchka.wav</Field>
</Item>
</MPL>
It only contains the Filename, no other tag. This appears to be a bug. If it was associated with sidecar or not, it should contain all the tags. "Filename" is never written as a tag to any normal file. There is a field called "Complete Name" which is the full directory and file path. However, in the iso and video sidecar files "Filename" is written. So, it appears to be associated with turning on writing to a sidecar.
The only way I can make this work is to turn off the sidecar for wav and aiff files and turn it back on for iso. If I leave it on and make big changes, i.e change genre on a group of albums, I generate literally hundreds of these one field name xml files.