i am seeing a plant that is growing good, i would not worry too much as of yet with the young plant
it is most likely the strain itself, meaning this is how that strain grows. real long heavy leaves.
it is the sativa influence in the pineapple express auto. i do recall when i grew one of these out it did the same but that was years and years ago, i do remember it was very nice smoke.
so right now compared to your other plants yes this one is different. but the difference should not worry you. as everything appears to be normal at least for this strain