There could be a few reasons why your pink princess philodendron lacks the iconic pink coloration - Inadequate indirect sunlight exposure Low humidity and dry air causing leaf scorch Compacted soil preventing drainage after watering Excessive mineral salts from overfertilization High amount of chlorine/fluorides in tap water Normal reversion of variegation as plant ages Newly unfolding leaves may take some time to develop color Carefully evaluate all probable causes and make suitable adjustments to remedy.