Double link name on TOC

Hi all, got a document, by some reason every time I’m updating the Index, if I’m using my Heading 1 format, appear twice on TOC.

But if I do open this file on Office, and do the update index too, got desired result, it means just appear one on TOC.

This the doc test I’m trying to fix.

Test-doc.docx

Any help is very welcome…

(Edit: activated screenshot -AK)

Right click in the index → Edit index → uncheck “Additional styles.”

Wow… very simple solution!!! Thanks a lot!!!