使用Saxon的Altova XML中的xsl：result-document的奇怪行为

my input file:

我的输入文件：

<folders>
    <folder name="a" level="1" metadataFile="LVM20metadata.tsv">
        <subfolder name="a/er" level="2" filter="no" />
        <subfolder name="a/ir" level="2" filter="yes" />
        <subfolder name="a/ar" level="2" filter="no" />
        <subfolder name="a/or" level="2" filter="yes" />
    </folder>
    <folder name="b" level="1" metadataFile="LVM21metadata.tsv">
        <subfolder name="b/er" level="2" filter="no" />
        <subfolder name="b/ir" level="2" filter="yes" />
        <subfolder name="b/ar" level="2" filter="no" />
        <subfolder name="b/or" level="2" filter="yes" />
    </folder>
</folders>
<folders>
    <folde