I really don't know if that is a bug or not, but it could be, so I post here. In the beach zone scenario (in ultimate of course, where it hurts the most) when the starting patch splits in two directions, from there heading right there is a bunch of space where you can't target your enemies (gees) but they can hit you, it's like the last mothmants from the ultima quest "earth in crysis 1" that could not be targeted.