Hello,
I have one page, which does not sync on the menu.
I remove the secondary language translation for that page (also remove it by "delete permanently" in the bin).
Then I go to the pages in the main language and click "+" to create a translation. I confirm the translated strings in Advanced Translation Editor. And the new page is created in the secondary language.
But the secondary language page is not available on the menu of the secondary language. I click synchronize menu, but it says that the page is not translated, so there is nothing to synchronize. How do I sync the page? Is there anything on troubleshooting page I need to click? I tried basic things like syncing taxonomies for pages, cleaning cache etc. But it did not help.
A 2 min video describing the issue is available at this link (there is an option to double the speed available): hidden link