I just discovered this today. I had this problem that I don't think I've ever heard reported before. The problem was a reoccurring one for me but it wasn't fully grasped when I took a look at the SA-5 in my 666th Upgrade LIB. When I was flying, with any time compression on, and a SAM locked onto and fired at me, the missile fired and after four or five seconds, it suddenly vanished from the RWR. I noticed not too far behind the SA-5 site, a fire burning. I didn't know what it was until I saw the next missile launch and the fire appear after the missile vanished. So I compared the SA-5 with a SAM missile that didn't vanish in time compression and soon enough I found that it was the acceleration setting. The maximum setting for the acceleration parameter is 16777216 and that is what I had the SA-5 set to while the other one was set to around 359827 or something of that nature. I changed the settings on the SA-5 and it launched, didn't vanish and blew me up when it hit.
Centurian