It only affects Deviants with long names. The health bar has been expanded to prevent names from going outside the UI.
Then maybe shorten these names please. I don't know about others, but for me (I hope not only) it is much more annoying when the life bar jumps from wide to narrow than whether mob is called "[Conqueror] Red Eyes. Leader of Howling Bloodthieves (Poison)" or "[Conqueror] Red Eyes." or "Mob number 1356". This game is constructed in such a way that it requires you to repeat certain things thousands of times. So more important than the name is how much and how often it annoys you.
Scaling UI is the new new bro. Why make smaller font when you can just enlarge the hp bar so that it goes over the frame? Duh.