Yes, it should be replaced, wood usually can not be “unwarped.” With time, it may go back but during the “curing” stage after the moisture has affected it, it will still have some warpage to it.
Your best bet is to contact the manufacturer directly, have the reciept of who you bought it from, most door manufacturers have excellent warranties. If in eight months it has warped, they may have had a bad stock of lumber from their mill, not the right amount % of moisture content. Here in Colorado my dad’s company would mill their wood (and only accept it) if the % was between 14 and 17% because we are so dry here.