Connection between ServiceBus properties AutoDeleteOnIdle and ForwardTo?

What is the relation between the ServiceBus properties AutoDeleteOnIdleand ForwardTo?

1. I have a ServiceBus queue with AutoDeleteOnIdle property set to max value, 10675199:2:48:5:4775807
2. I am updating the queue property AutoDeleteOnIdle  to hold value 2 days
3. Upon setting the ForwardTo property to another queue, theAutoDeleteOnIdle value gets reset to 10675199:2:48:5:4775807.

I am using ServiceBusExplorer to perform the above mentioned update operations. Clarity on why AutoDeleteOnIdle sets to max value on defining ForwardTo will be of great help.