Import mode "MERGE" and "MERGE_PROPERTIES" still remove properties during import

Although it is clearly stated in "https://jackrabbit.apache.org/filevault/importmode.html" that no content should be deleted for "MERGE", this still happens.

I have tried with "MERGE_PROPERTIES" mode as well.

1. First, install test1.zip.
2. It will create nodes under -> /content/dam/de
3. then install  test2-merge-properties-1.0-SNAPSHOT
4. It will delete all the nodes under  /content/dam/de

           Filter used:

           <filter root="/content/dam/de" mode="merge_properties" />

kwin / tripod Please check if you can help with this.