L1 support requested to terminate an EC2 instance on which one of our apps seemed to be misbehaving. The node was terminated after few min.

L1 later realized that that instance didn't belong to that app, but instead it was one of the RabbitMQ nodes.

Then, after some panicking we remembered that HA was enabled, so nothing should've been lost.

Later, we realized that the recent RMQ upgrade necessitated a new cluster on which HA was NOT enabled!