The Soul Maw passive in the Lich tree lists “Requires Necromancer level 50”.
Confirmed! Thanks for the report, we’ll get this fixed up.
This appears to not just be a display issue.
This will be fixed in our next patch.
As I now belatedly understand, having worked my Lich up to lvl 50 so she could get Soul Maw, when you say “it’s not just a display issue,” you mean that she really does have to be a lvl 50 Necro to take it.