Disconnects caused by essence monsters

I have experienced several disconnects in the following situation:

- I encounter a monster with several essences on it, I use a vaal orb on the monster, and proceed to fight it.
- I walk away from the monster to regenerate some health, ES or flask charges.
- When I return to fight the monster, the game disconnects with '> An unexpected disconnection occurred' message. This occurs when the monster is 1 to 1.5 screens away from me.