Multiple Subscriber RIB Threads picking messages with the same ID value instead of the same subscrib

In our environment we are noticing that multiple shipment for same BOL number are getting for the multiple ASNOut messages that are bridged for the BOL as cartons get scanned out. This is happening since multiple threads are processing these messages.

We need to know why the messages with the same ID is getting picked up by different threads?

Since ID is the same, RIB should be processing all messages of a specific ID using the same thread. Has anyone come across this issue before and were able to resolve it?

Within RIB, multiple Subscriber RIB Threads are picking messages with the same ID value instead of the same subscriber thread processing all messages for the same ID.