I noticed a similar placement of 3 cyberdiscs in my current game (superhuman) on terror mission 1, I thought this was just a random fluke of ai placement. My poor mortar tank took some pasting coming off the ramp, thankfully I use improved ground tanks and usually have explosion height @ 3 as less than 3 doesn't make sense to me by the laws of physics! In a sense with explosion height variable in the advanced options this really is a major exploit u can take advantage of.