Is this an indoor palm or one outdoors? Potted or in the ground? How old? Yellow fronds could be a sign of poor drainage (don't let it sit in a saucer of water), or too much sun/lack of sunlight or even spider mites. From the photo you sent I see the yellow is from the center of the leaves, which is most unusual. The plant looks otherwise healthy so I am going to suggest you just wait and see if is a passing virus. Like us humans, sometimes the best cure for an ailment is to let time heal. Let us know how it looks in a few months. Keep growing, Marianne Binetti