With Azure Service Bus messages will be re-processed when a message is not actioned by the receiving party. An action would be completing, deferring, dead-lettering. If you don't have any of those, once LockDuration
on the broker side expires, the message will be re-delivered. Additional situation when a message would be re-delivered w/o waiting for LockDuration
to time out would be to abandon a message. Then a message is picked up right away by the next request for new messages.
You should share your code to provide enough context. Messages can be received manually using MessageReceiver.ReceiveAsync()
or using user-callback API. For the first option you have to action messages (complete for example). For the other option, there's a configuration API where you could opt-out of auto-completion and would be required manually complete message passed into user-callback.