While i reviewed the organic search visits through "Last Touch Channel by Search Engines - Natural ", i found that most organic search visits from Haosou(so.com) can't been counted in July 2017.
The average monthly organic search visits from Haosou(so.com) is more than 10,000 and it dropped 500 visits in July 2017. i am not sure whether most of the visits was counted as refer traffic.
Do Omniture make some changes for the traffic analysis with Haosou(so.com) from July 2017?
Adobe typically adds changes to social networks and search engines in maintenance release notes. In addition, Adobe will never touch Marketing Channel Processing Rules.
I would recommend double checking to see if changes were made to the processing rules.