The issues appear to be connectivity issues, causing issues with making changes to campaigns. This is only impacting those campaigns with position preference enabled, said Google.
One advertiser received a response from Google on the issue:
After we ended our call, I escalated this issue to our Technical Team. While reviewing your account, they recognized that you have been unable to download your campaign into Editor because it has position preference enabled. Fortunately, they are aware that some users are currently having this technical problem with AdWords Editor, and it affects all campaigns which have position preference enabled. Due to this technical issue, campaigns with position preference enabled cannot be downloaded in AdWords Editor right now.
We regret any inconvenience this has caused you, but please be assured that our engineering team is working hard on the problem, and we hope to have it fixed very shortly.
A couple weeks ago we reported similar issues with the AdWords Editor, but they seemed to then have been resolved. These may be lingering issues from that issue?