When I enter a UFO, parts of the outline which show the UFO's shape are covered in white triangles that are a quarter of a tile in size, and sometimes there are black shapes jutting out from the outline of the UFO and covering terrain. Furthermore, UFO interior walls are invisible but otherwise block line of sight and shots normally.
I haven't seen this happen with light scouts, but it does happen with scouts, corvettes, landing ships, and cruisers, which are the UFOs I have encountered so far in this playthrough.
