Deletion in the main wiki while using the override feature of the filter app on a subwiki

Steps to reproduce:
1) Create a subwiki
2) Install the filter app converter application on main wiki
3) Set input type to xwiki+xar/1.2
4) Set output type to xwiki+instance
5) Set a source file to a xar file, for exemple containing an export of the Main space
6) Set default reference of output to subwiki:Main.WebHome
7) Set Delete existing document to true
8) Proceed to export

Expected: The XAR is imported in the subwiki, existing documents being deleted and imported fresh. In our example, the Main space of the subwiki is deleted in imported

Actual result: The Main Space of the main wiki is deleted, not sure about the subwiki, but the documents are imported. The restore of a document in Main Space of the main wiki (i.e. xwiki:Main.WebHome) cause the restore of the equivalent subwiki document in the main wiki (i.e. subwiki:Main.WebHome as it was before import).