A user has uncovered that if you have a result list configured to 'Open first document of the result list automatically in the Viewer', 3 'Open' entries are created in that document's history log after doing a search.
In addition, opening the document history itself creates another 'Open' entry in the log.
Those that examine document history closely may see 6 or 7 'Open" entries after viewing the document only once.
I'm not sure I would refer to this as a bug as I have know idea what mechanism is used to track document activity, but it does appear somewhat confusing in an environment where this is used and examined closely.
Any clues appreciated.