How does Resolve create AAFs?

I am scratching my head. I am preparing ALEXA and RED material in Resolve for offline in AVID MC8 (which I don't actually have access to). Usually, I create an AAF and an ALE from my timelines after rendering DNxHD36 files for each mag and that works fine. However, sometimes the editor complains that the AAF does not work. To test this, I re-import any of my sweet AAFs into Resolve and see that they link to (and automatically import) the MXF files. With the AAFs that do not work, on re-importing they link to the original camera files. I can't see any reasons why they sometimes link to MXF and sometimes not. How does it work? Has Resolve somehow "forgotten" about my MXF export? How can I remind it?
Thanks for your help!
Steffen

I have actually now got a theory: It seems I have to create AAF and ALE directly after the transcode, with the offline MXF files present at the location I exported them to. If I move the MXF files to another folder or unmount the drive they are on and then create the metadata files, they won't work in AVID and they will link to the original camera files on re-import in Resolve, even if at that time the MXF files are present again.
Can anybody find that in the manual?

I am still really interested in any info on how Resolve handles the connection between timelines and exported files. Somewhere in the DB must be fields that record this information. It appears for example in the UNC field of an exported ALE. Is there any way of accessing / manipulating this data directly? Can anybody shine light on this?