Reply detection isn't marking threads as replied

This usually happens when the reply lands in a folder our reply-detection isn't scanning — if you have any inbox rules/filters that move replies out of the main inbox (into a separate folder, label, or category) before we can process them, they won't get matched. Can you check whether any filters might be redirecting replies from this campaign, and if so, either disable that filter for this sending address or add an exception for it?