I already bug reported this under graphics, and in a quick search of this forum I don't see it mentioned.
I logged into my Wizard in U17, after update, and found that when I cast spells I only see single digit damage on the screen. The combat log does appear to show full damage. It appears to only show the first digit, but I can't be entirely sure.
At first I was only doing -1, -2 damage, but that doesn't seem to be the case. Monster appear to die appropriately after appropriate damage. For example, a meteor swarm did 48 damage and shows up as a -4 on the screen.
Anyone else seeing this?