Good catch!
Managed to fix it, for whatever reason, the code for UI text was getting a height value half of what it was getting for normal text, so it wasn't working correctly.
I'll publish the (GC-free) fix in just a minute, but a hotfix is...
On line 3362, swap out all instances of "rawBottomRightBounds.y" with "rawBottomRightBounds.y * (uiMode ? 2f : 1f)".