This may be an old problem, but a friend just reported this and I wanted to pass it along.
Under FCP 4.1:
1) Load a clip into the Viewer
2) Set the in and out so you have handles
3) Place the clip on the timeline
4) Reverse the clip (say at 100% speed)
5) Verify the in and out using timecode overlay in the Canvas
6) Double-click the cllp to load it into the Viewer
7) The out has moved in the clip loaded into the Viewer
8) Reverse the clip again (also at 100% speed)
9) The clip in the viewer goes green
10) The in and the out have moved on the clip in the timeline.
I haven't tested this with Frame Blending off to see if this makes a difference.
Larry