So I spent a lot of time trying to reproduce it and provide you with a relevant save game. And it appears that with the new pathfinding a few biters from larger groups can make it through my defense and settle somewhere behind. So i was totally wrong

You can discard this report then !

Hi,

My current game's base is protected by a "security perimeter" of laser towers guarding the intervals between lakes. The inside is explored and cleared of any biters. It was perfectly effective in 0.16.

Now in 0.17 from time to time I get attacks inside the perimeter. Those seem to come from ...