I have the same problem but only with the odd aircraft. Once at Gatwick on FS2004 a (Aardvark) BA
737-500 was coming into land, but its approach was really weird. It would nose dive a long way down then pulled back up and went up about half the altitude it went down. Then it finally was about ground level right at the end of the runway and contacted tower that it went missed.
Also with Project Opensky B747-400's when they come into land they just disappear when they touch down. I don't know why?