It seems to me there is some transitioning of the plants getting used to the new environment.
To me, it seems the tall plant is unusually tall for a plant grown and raised in it's lifetime all underwater, and more than likely it was raised in a nursery where it was grown with it's leaves in air, not water.
Plant sellers get the plants to a marketable size and away they go as fast as possible to be purchased and these would have been much smaller imho
if grown underwater.
It might be good to know, ask the manager if they know how the (tall) plants arrived at the store. Wrapped in paper, in bags of water??? And if they know
if they were grown under water or not. Most will not know. Or if it is a named vendor usually you can find out how they raise their plants.
Anyhow there is usually some issues in transitioning nursery air grown plants to underwater in your aquarium. You might see new under water leaves coming up in the next couple weeks. They might look a bit different.