Just thought I'd share this in case it happens to anyone else.
So I was doing the open skies achievement quests a map at a time and in order. I completed up to the domain of Vabbi achievements, but when I thought I had finished I noticed that the "Open Skies: Elon Riverlands" had reverted back to incomplete and only two items obtained, those being the two from the heart quests. I did not receive my 50g back. The main problem is that I don't have the Sadi equipment finding quest achievement, but it's complete and I have the mini reward from it still. So I can't actually complete it again to get the achievement back. I submitted a ticket, hopefully they fix it.