I've seen this on brand new B6 chargers (both genuine and clones) and nearly new lipos... I think there can be times where the system drops to trickle charging/balancing and it is taking out about as much current while checking the voltage on each cell as it is putting back in. So far this is only happening to me on smaller 2s packs.

To be honest, I haven't noticed the problem since I started using a decent hobby style power supply.