The updated Qtum Core v29.1 includes upgrades from Bitcoin Core 29, like better orphan handling. If you're running a Qtum node and you receive an orphaned transaction, your node will efficiently request additional information from reliable peers to figure out what to do. This way the node does not rely on information from a single peer, it tracks all the candidates that announce the transaction. The Qtum blockchain is designed to offer a 32 second block target, which is considerably faster than Bitcoin's 600 second target. With the speed comes the problems, we're basically trying to get hundreds or thousands of nodes around the world stay in sync, so this should definitely help with transaction propagation.