On low sometimes mechs at 1200 yards or so will not be rendered. I found out the hard way when an invisible Gausscat started sniping me. I saw the Gauss rounds materialize in midair and come towards me. A few moments later a light got within sensor range of the cat and I saw an empty red square where a mech should've been.
I think I've fixed this by raising some the graphics settings. Shouldn't happen on any graphics setting. I noticed this a while back too.
Edited by xenoglyph, 21 November 2012 - 10:13 PM.