Help my zombified piglins has the same texture as before

my zombified piglin has the same texture as the zombie pigman? I bought the game. Its on 1.16.1, when i enter my nether all i see is the old pigmans not the new version. Ive even waited to open my portal until the update. In my other worlds there is no issue, the zombiefied piglin has the new texture but not my survival world can u please fix this?