Installed FCP Studio this weekend. Have a project I tweaked two clips for in Motion. "Send to Motion" didn't work right so figured the get-around would be to export from FCP a .mov file, bring into Motion for tweaking then export clip from Motion as .mov file. Project is HDV 1080i/60; dimensions: 1440 x 1080.
Imported fine into FCP and laid clip into timeline. Dropped MB2 filter on clip only to discover right side of clip frame -- a bit more than one-tenth of the frame -- is blank, as if the width dimensions are off (squashed). In other words, if there's video on the underlying layer of the timeline, that video is visible in the right side sliver that's missing from the newly imported clip.
So back in Motion I export at 1920 x 1080 and re-import. No difference. The left side of clip won't fill frame. Screenshots below to help clarify: