I have seen the Full Metal series and the movie but wasn't fortunate enough to find the movie in AVC. Had a heck of a time getting the whole series. Seemed to get hooked on this one.
There actually was a reported instance (more like lots of people) of a particular release of Matroska causing seeking and random crash issues for H.264 this was supposedly corrected. This was not only a VLC problem. Sorry I don't remember the particular version but the time frame is correct at about Dec 05. Given that the problem was an encoding issue it will take time for the files to disappear (if ever).
I have only a couple of files on my machine at the moment and both are earlier than yours. Both show slow seeking and sometime a blochish tendency, but never crashes. VLC tries to stay current with Matroska so with this one any problems between H.264 and Matroska are resolved quickly.
AVC is new and we are all learning. There are always a few problems along the way and hopefully it will be what we have anticipated.