Description: Search results are ranked chronologically but based on the last activity time of a conversation containing a match, and not based on the activity time of the search match in the conversation. For example for the search query: email@example.com shipment order
First result - old match and recent activity: Conversation thread with firstname.lastname@example.org with a reply from TODAY but the last mention of "shipment order" was 1 month ago
Second result - more recent match but older activity: Conversation thread with email@example.com with a reply from YESTERDAY including "shipment order"
Note that this is similar to what Gmail is doing, but not Outlook*