For the past few sundays I've had 2 of my newer sites hit #4 for very competitive keywords. They would stick for maybe a few hours and go back to where they have been sitting (page 5 and 14). Last night, one stuck at #4 for about a day and disappeared this morning to page 5+. Has anyone else experienced this and know why? It looks like a filter or penalty being unapplied then applied again. Question is what kind of filter? Age, Not enough links, ect. Any insight would be appreciated.