NetNewsWire 3.2.15 fixes a number of syncing bugs:
Fixed at least one cause of a bug where syncing could appear to get stuck. (It would sometimes start but not finish and the indicator would keep spinning.)
Fixed a bug where synced feeds wouldn’t get Growl notifications.
Fixed a bug where synced feeds that are suspended would get refreshed anyway.
Fixed a bug downloading enclosures for synced feeds.
Stop button now works for syncing in the Activity window.
Fixed a bug logging into Google Reader where it could lock up the UI.
As always, you can download it manually, or do a Check for Updates in NetNewsWire.