This a bit of a guess, as I use Project Manager in PrPro, and it has some major differences.
I suspect that you have a large Clip, or Clips, and have used Instances of that/those on the Timeline. Is that the case?
If you had discrete, separate Clips, that had been Trimmed, in either the Source Monitor, or on the Timeline, then those would be Trimmed, with X Frames as Handles.
Discrete Clips are different than Instances of a larger "master Clip."
Maybe someone else will chime in, and either validate my thoughts, or tell us both, where I am going wrong.
Thanks for the reply. I have tested this multiple ways now. My last test I took a single 2 min clip, set in and out points 10 secs apart in the clip monitor. Dragged the 10 secs clip to the timeline. Then archived the project. It archived the entire clip. I have also tried it with a project with multiple clips. The only thing that archiving is doing is removing unused clips, no trimming at all. It really makes the archiving function useless. I used to use Premiere Pro (very old version which which not handle the avchd files) and archiving did the job very effectively so it is disappointing to have this problem.
That probably blows my theory then.
Thank you for reporting,