Bookmarks in subfolders not showing 4 level onwards (Firefox, Apple OSX High Sierra)

Hi, my bookmarks are not showing in subfolders 4th level onwards (inclusive).

Im using Eversync, and I have used for years now. First time Im having this problem.

The issue happens on my mac. Im using the latest firefox version 57.0.1, on a macbookpro mid 2015 with OSX High Sierra (10.13.2). Im using 2 other Add-ons ("Adblock" plus and "Tree Style Tab", all of which are also up-to-date). Im logged into the eversync while using firefox. Is there anything I can do to make this work?

Im also using a similar firefox configuration on another machine, running windows 7, and all bookmarks are showing and getting synchronized with Eversync.

Any tips would be welcomed :)

Thanks

Best
--
Sergio