When xchain gets behind the blockchain and catches up, transactions that are already confirmed with more than 6 confirmations are never sent to subscribers.
This only happens when XChain gets catastrophically behind (more than 400 confirmations or 3 days) and has to skip blocks to catch up. This is a situation that should not occur in practice.
When xchain gets behind the blockchain and catches up, transactions that are already confirmed with more than 6 confirmations are never sent to subscribers.