"/auc bid < amount >" sometimes results in unwanted effects such as:

• Placing a bid higher than you typed
• Placing a bid lower than you typed

Sreenshots:

Bidding 56010 > placed bid 75050
http://imgur.com/WQ9gh

Bidding 4000 > placed bid 1005
http://imgur.com/l6IjH

Not a bug. Conceptually, every participant can bid as much as they're willing to pay. They only end up paying enough to beat the minimum price as well as the next highest bid, by a configurable interval. The actual bid size is always kept hidden.