Looks like normal plant melt.
Most plants are cultivated emersed. Thats with the plants only partially in water with the leaves above where they have ready access to atmospheric CO2. This makes them grow faster and are more commercially viable.
You take that plant, completely submerge it your aquarium and the CO2 mostly gets cut off. The leaf structure needs to change to one that can get its CO2 from the water. It does this by using the stored carbon in the leafs (hence the melt) and growing new leafs which are more suited to its new environment. You may lose all the original growth but its new growth you need to look for.
2 weeks isnt enough time to judge the long term of your plants.