Serious XML problem, audio is truncated on export

Question

I edited a video in FCPX, then I exported the XML, graded in DaVinci Resolve 8.2 then I imported the new XML back into FCPX.
in the new project created from the new XML, I had to add a music soundtrack.
the BIG problem is that when you export the new movie, the audio track is truncated.
I discovered that it's specifically truncated where the original XML duration was ending.
example: in my case the original sequence ended at 2:05, and so it was graded in Resolve and ending also at 2:05 – when I imported the new XML into FCPX, I added some titles and audio track, increasing the duration of the sequence to 2:20.
it turns out that for some reason, the audio is truncated exactly at 2:05 even if you can see it and hear it correctly on the timeline – the problem is only on the exported movie.
note that the exported video isn't truncated, only the audio.
anyone had the same problem?
it would be interesting to nail it down to an FCP XML bug or maybe a Resolve XML export bug.
I will file a bug report both to Apple and Blackmagic.

Answer 1

Just an offhand guess here. Try wrapping everything as a compound clip for final export -- see if that keeps all your audio at the end. That should force an update to the fcpxml (length). I have noticed some bizarre behaviors in fcpxml*, so what might have happened is the new audio you added was attached to a "subclip" (a clip within another clip) which would be "trimmed" by the parent. If the editing applications (including FCPX) did not update the length of the parent after the addition of the extra material... you get the gist. 
I've always had the impression that apps like Resolve (and Color) should be the *absolute* final step before export/finalizing a project. The use of these apps are not part of a "back-and-forth" workflow between apps. If you can get back to a stage in your project before Resolve, try adding all your last minute content again before going back into Resolve.
*I've had one fcpxml file generated where *every* title I added over the entire storyline was added to every clip in the xml, even though no more than two titles were ever attached to any single clip... go figure; very corrupted and nothing I do to the project will fix the xml output. Fcpxml is a headache to try and deal with and the documentation *****. For instance, all times are divisions of integers. If a project or clip has a 29.97 frame rate, you do all the math at 29.97 then at the end, multiply the fractional part by 30... or you won't get a frame accurate result ----- I THINK because... IT'S NOT IN THE DOCUMENTATION. But so far that's the way it seems to work. At any rate, if Blackmagic or anybody else has problems dealing with fcpxml... I can certainly understand why. It's probably better to export video for each step and skip the fcpxml BS for awhile until everybody gets it straightened out. [If anyone reading this knows the ins/outs of fcpxml - I would like to start a conversation with you because I'd like to write some online "apps" that take the fcpxml as input - starting with finishing my project that generates chapter markers (for QT and or Compressor).]