For me, it started around Aug 23, 2015.
I get a captcha which I answer and it asks a second capcha (may be because I have two deliveries in queue?).
At the end I get a "Capcha successfully confirmed. Please login again".
If I refresh or wait until Deliveries refreshes by itself, the captchas start again.
Therefore I have no amazon updates since two days now.
Is there a workaround?
Btw., I had these captchas from time to time in the past, but answering them always worked.
(Note, I'm asking from a different account than I purchased Deliveries)