My Washingtonia Robusta had a new frond growing, and I noticed that it was appearing brown. It grew some more and then I noticed it started growing green again(like the top half of the frond green, then a brown line from side to side in the middle and then the bottum half green). The frond just rips and bends back and forth form the brown line. I cut the frond all the way down to the brown spot since it would have ripped off from a windy day. Is this just like some weird defective growing? I know the palm aint dead, since i pulled on the frond it didnt come out, and the remaining part of the frond is green.