I suspect a bunch of text that was previously in the old sans-serif UI font has gone missing – the Angel/Demon reward descriptions were the most noticable, but also I’ve spotted (a) there’s banner on the Quick Battle screen in PvP Blood Frenzy regions is empty, missing the “Blood Frenzy is active” text, (b) the Journey overview screen is missing the text naming the restrictions and the event captains. And this. And I bet there’s more.
Odd though that it’s not all the old font? like in this screenshot, the “+26%” and “Morale Bonus” text is still in the old font and are rendered OK.