I just experienced something new to me twice 1 each round.
Backwater
North west facility/base that have the blue pipes that run through it. Behind building with roof windows
Arrows go through FT members or bend direction like if the FT have a object infront of them.
Than shortly after framerate drops really bad. Unsure if the FT experienced anything funny.
2nd time was in overgrowth.
Frame rate dropped when attscking FT and arrows going through targets