Fairly sure it's the IGL change, Jexen was still there when they changed to Knight IGL and that didn't work. Internal conflicts over who should IGL then caused Jexen to leave. Even though he's back now he's not contributing as much as he did before
You should reread my reply. Biank didn't want to IGL anymore, so Knight had to IGL for a few months - since this didn't work, they brought in B3ar as IGL