Bundle file content lost after modifying visibility

This morning I opened the project on Studio and I found that all the customization made in the nuxeo-PROJECT_NAME-bundle.html file have been automatically removed; I found only the last result selection action that I modified:

<link rel="import" href="elements/fdm-merge-pdf-preview.html">
<!-- Contribution of element 'fdm-merge-pdf-preview' for slot 'RESULTS_SELECTION_ACTIONS' -->
<nuxeo-slot-content name="fdmMergePdfPreviewAction" slot="RESULTS_SELECTION_ACTIONS" order="1">
  <template>
    <nuxeo-filter group="Payout Users,PAYOUT_USER" user="[[user]]">
      <template>
        <fdm-merge-pdf-preview icon="icons:archive" label="Anteprima" pdf-to-merge="[[selectedItems]]"></fdm-merge-pdf-preview>
      </template>
    </nuxeo-filter>
  </template>
</nuxeo-slot-content>

I can go back and reinstall a backup (see attached version), but can you please check if something went wrong in synchronization? Have you ever found this problem?

I reproduced the problem:

When I edit the visibility of the pages in the DESIGNER > UI, the custom bundle file is modified by the Studio and the manual changes like the documentViewPage are lost.

See attached files (bundle.html is before and bundle-studio.html is after modification)