I'm running the 2.3 release version for windows on xp and I cant gain entry to the upper floor of a landed harvester. The left doorway side of the two doors providing entry into the ufo is blocked some how by invisible unpathable terrain. You see normal floor tiles but you wont be allowed to walk on it. The right side is accessible thou, but there is another blockage on the right side at the doorway to the stairs leading to the 2nd floor. Issues like this happened in the 2.3 dev release too, although in a different form, as in previous releases I've only seen inaccessible 2nd floors.