There is actually nothing wrong with them!
Many Amazon swords show their nervature especially in the newer leaves.
Depending on their original population, the plants show their veins more or less prominently. This can be seen especially when comparing the formerly different species: Echinodorus grisebachii
, E. amazonicus
, E. bleherae
(yes, that's the proper way to write it), E. parviflorus
which are all now synonymized under one name: E.grisebachii
The only thing wrong in the setup is that these swords will outgrow your tank in no time!