I merged many new pulls into 720Beta but now mastery is only hidden for Mastery Rating on my low level characters. Regular mastery is still yellow on low level characters.

Not exactly clear what did you mean here but I believe there are inconsistences in displaying mastery and mastery rating names for low level characters. Found a possible reason why it happens. But first will probably need to check that everything what was intended for merging is merged.
Edit. Interesting that in not-merged version I see the correct code.

Fixed in #61