I wouldn't be surprised if Google had their eye on managing some of the larger clients themselves.
Its another reason I never put all my clients under one Adwords professional Google type of account, or whatever its called. I haven't trusted Google for a very long time.
It wouldn't surprise me if they've divided Adwords accounts into two types..
1) Acounts they ran the profit maximising algo against.
2) Accounts they would eventually like to 'manage' themselves.
Possibly there is a third type in between that just gets shut down the better to manipulate the bids on 2)