is one piece episode 641 filler?

Robin woke up to find a bunch of dwarves climbing on her looking for anything suspicious, much to her shock. When she tried to get up, a certain dwarf by the name of Leo informed her that she better stay down, while another named Kabu informed the other dwarves that she used a weird magic.

She then recalls how she captured Kabu but how she was then knocked out by an anesthetic flower along with Usopp. After that she is informed that she is currently located under the forest of Green Bit and that she should not try to escape as she is sewn to the ground due to the power of Nui Nui.