Exception "Buffer Underflow" in Seepage Map

I tested a bit and im sure the Exception is thrown when i run towards the last two Rares in the top right of the map.
I did a breach and killed all the monsters that were not in the top right corner, even stayed a few minutes in the map and did nothing.
As soon as i ran towards the rares, at approx the same point my game crashed.
Did this 4 times or so.

Hope it helps, keep up the good work :)