My apologies if this is inadequate as a report, or if it's been reported already. In playing a mission at the Manor House (I think that was the name, big house, complex map of many layers & ramps, UFO on the helipad out to the right as you start), I found a problem in movement.
The garden pond seems to have a large impassible area around it, where my squaddies would not go. Combined with the benches & hedges, and a stray civilian in the area, it posed a huge obstacle. The movement box just would not appear within about 2 squares or so around the visible water, possibly a rectangle the size of it's largest dimensions.