https://bugs.documentfoundation.org/show_bug.cgi?id=170272
--- Comment #2 from Denis <[email protected]> --- I found the exact cause—distinct from the previous bug—and fixed both files. The issue: when LibreOffice generates labels via mail merge using your template, it internally renames all linked sections with a prefix like `MailMergeSection2026-09-15T17:10:54Z...` (e.g., `MasterContact` becomes `MailMergeSection...Z11MasterContact`). The problem is that the `text:section-source` references for the 7 synchronized labels are not updated; they continue to point to the old name, `MasterContact`, which no longer exists in the document. As long as you don't touch anything, the issue isn't visible: the content generated during the mail merge remains displayed as is. However, as soon as you click "Synchronize" (or LibreOffice updates the links, for instance after an edit), it looks for the `MasterContact` source section, fails to find it, and clears the content instead of leaving it intact. A comparison of your two files confirms this: all 10 field types (Contact, Conso, Details, Time, Weight, Degrees, Description, Title, Code, Date) were pointing to obsolete section names. The fix: I matched each broken reference to the actual current name of its master section in both files and then re-ran a clean synchronization—all content (including your 7 labels) is now back and correctly linked. Good to know for the future: this bug stems from LibreOffice's mail merge engine itself (not your template), so it will recur every time you generate new labels until the underlying issue is fixed. If you like, I can prepare a small reusable script for you (or you can send the generated files back to me) to apply this fix automatically after every mail merge, before clicking "Synchronize." -- You are receiving this mail because: You are the assignee for the bug.
