Also documented here:

Market Complete - Take All does not work on first try under certain conditions

My experience was that closing the Market window, then re-opening and going straight to the Completed tab allowed this to work, but something happens while browsing or buying items that causes it to fail.

Yes it does. Just take 1 item, then the take all button will work. Never fails...

let s change the button title: take one and after take all.

thank you for reporting this bug.
A fix will probably be deployed in Patch 3 for Hector.

hmm this guy looks like he is a newcomer to the team :]

update on that bug:
the fix that will deploy with patch 3 unfortunately won't fix all problems with the take-all button
we keep on working on that.

also noticed that. Since the normal take out buttons work its not that heavy