I noticed this a bit more since Mobs don't migrate that much anymore, that they get stuck on uneven terrain. It must not even be a steep hill, a smaller one, that you can barely hide behind (not higher than a runner), might be enough. They come unstuck sometimes, but not necessarily before their death. I have seen it affecting Warbots and Mad Copbots in K 01. Not seen it yet on Spiderbots.
