I have duplicated this on a server and a creative world. I connect a plug to an Capacitor Bank and then a point on any other energy storage or machine and even at zero capacity it will continue to drain power.

It seems to do it only when the source (plug) is a capacitor bank, but the destination (point) can be anything. So I don't know if this is a Flux Networks bug or Ender IO. I am on FTB Beyond 1.7.0.

Source: http://imgur.com/a/0N6kE

Destination: http://imgur.com/a/qofva

Can confirm this in 1.10.2. I was just playing around trying to understand some of the transfer options and I setup a test with 1 Ender IO Vibrant capacitor with a plug, and three (connected) Vibrant Capacitors with a Flux point. I was able to fill all three capacitors from the single source capacitor and it just kept going when I added a few more on.

Fixed in dev