Very strange. Your description of your plant's care pretty much eliminates the likely causes of such symptoms on a palm. There is always the possibility of some unusual disease, but I doubt that seriously as your area is obviously not filled with palms which would support such a problem.
Something seems wrong in the roots. Perhaps if it was transplanted, this could be a temporary setback. That palm would like a medium to bright light and so I'm not sure what else to recommend but time and moderate soil moisture. Fertilize the plant with a soluble plant food at the label rate once a week to see if it just needs a little more nutrients such as nitrogen.
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