I thought this was interesting - on the web:
https://www.totalga.com/document/FAME%20Bulletin.pdf
and the attachment to it ( NE-09-25 ).
The industry has obviously recognized the issue and are taking steps to address it. If the AAIB hasnt yet positively discounted this by doing the GC-MS analysis to rule out FAME contamination then they need to. If they have, then they should say so.