My daughter's WISV-IV was similar. Gifted processing score but the other scores were average range. She is not academically gifted but was actually tested for LDs. We just assumed that her quick, fast handwriting helped her earn such a good processing speed score. She does enjoy art and has excellent fine motor skills. She struggled with reading and spelling (as well as the other academic subjects).
Usually on this board we hear of the children with lower processing scores and other gifted indexes--not many seem to have the opposite testing profile.