I am using Firefox Nightly on my Mac and Firefox Aurora on Android. A few weeks ago, sorry, but I do not remember when exactly, my bookmarks got "shuffled", bookmark order in folders was lost. This happens in a repeatable fashion now. Steps to reproduce: - Move a bookmark on Mac - Trigger sync on Mac - Trigger sync on Android - Trigger sync on Mac - Trigger sync on Android What happens: - Bookmark jumps back to former position on Mac Expected: - Bookmark stays where it was moved I have installed https://addons.mozilla.org/en-US/firefox/addon/about-sync/ where validation shows some errors (not only) for bookmarks Maybe this is related, I have attached the export of that. I hope this helps to find issues in sync code. Is there a way to resolve the validation errors locally? Or should I use about:support and refresh Nightly / Aurora?

Thanks for the report! This is almost certainly bug 1352947 and bug 1352931, and we are tracking this via the meta bug 1353641. At this stage we can reproduce the issue and we'll update this bug when we have a fix landed.

Rolling this into the meta-bug.