Hello
I’m kinda new to Scrivener, so I’m not sure if I’m doing the right thing
I’m trying to create a new format for my paper, using specific font(s). Whenever I change the font it reverts back automatically to another one. Please check this screencast
https://recordit.co/lyJGnhsJPD
Please advise
Interesting! It looks like maybe that some of those fonts should not be available for selection in the first place. You can reproduce this problem in the main editor itself. If you select some text and try to apply one of these problematic fonts, it will instantly revert to Lucida Grande.
One of the first things I always check when running into stuff like this is TextEdit (which uses the same text engine and font handling Scrivener does). I was surprised to find that the font itself isn’t even listed in the toolbar font selection dropdown menu. So I tried opening the font panel instead (⌘T), and found it there. Upon attempting to select it, as you might expect, I got the same exact result. Lucida Grande was the font that ended up being applied to the text.
So this appears to be a Mac bug of some sort. Perhaps these fonts are meant to be internal only, and they are showing up in font selection tools system-wide. Perhaps even further, the developer(s) of TextEdit thought they could just get around the problem by hiding the fonts in their own menu—of course that doesn’t solve how fonts work in every other program. 
At any rate, the clear answer seems to be to use another font. I would use TextEdit’s font menu as a reference for what should work.