Major Description
Test 28 creates a sender and the fallback receiver on a single edge router and a primary receiver on an edge router three router-hops away. When the primary receiver connects then the sender starts sending but the messages are received by the fallback receiver on the sender's local router and not by the primary receiver.
The fix is to check the messages' receiver during test phase 0 and to release messages that arrive on the wrong receiver.
Note that fixing this reveals another problem where the sender router is not notified of the disappearance of the primary receiver. This problem will be treated as a separate issue.