Tooltips in enchantment table UI are inaccurate

The only steps I took to create this was what's shown in this video, I mouse up from the second level enchant to the first but the tooltip doesn't change, until the next time I mouse over it again.

To reproduce

1. Place an enchanting table
2. Put an enchantable item in it
3. Move your mouse on the bottom edge of button 3
   You will see that the button is highlighted, but you don’t see the tooltip.

Or:

1. Place an enchanting table
2. Put an enchantable item in it
3. Move your mouse on the bottom edge of button 1 or 2
4. Click the button
   You might get a different enchantment than the one in the tooltip