While you could not run out of your voting mana before HF, you can do so now. Before, each 100% took 2% of the remaining VM. So a 100% vote used to cost "only" 1% when you had 50% VM.

Now, each 100% costs you 2% of the total VM regardless of your current balance. So if you give away 50 full upvotes, you can run out of your mana.

Is it understandable?