Browsing MQ messages in Anypoint Platform can cause them to be routed to DLQ

QUESTION

Could browsing messages in Anypoint Platform (MQ -> Select Queue -> Message Browser) cause messages to end up in the DLQ (Dead Letter Queue)?

ANSWER

Yes, as per our documentation of Anypoint MQ, returning messages to the queue is a not-acknowledgment operation (NACK) and If you leave the Message Browser page, messages automatically return to the queue. This means if a message's redelivery count is just one less than the queue's "Delivery attempts before reroute" limit, browsing that particular message will make it reach the limit, and the message will be sent to the DLQ.

ADDITIONAL INFORMATION

Based on this, setting the Delivery attempts before reroute to 1 would cause every single message that has been queried by the Message Browser to be sent to the DLQ. 
Please be aware of this behaviour and set Delivery attempts before reroute accordingly. 

Assuming the delivery attempts before rerouting were set to 3, and the message was delivered twice via an application with NACK responses both times, if the same message was browsed from the UI, causing the threshold to be met, it will then be routed to the DLQ.