Hello,
You should avoid making more problems than which you solve. You haven't positively identified the plant. If the species happens to be a derivative of
Hygrophila polysperma 'Rosanervig'
for example, then this is normal behavior and you should take no further action. For verification, closely examine the OTHER plants in the tank, especially the stem plants, and see if they are discolored or pale. If not, then there is a lower probability of a general nutrient shortage.
In general,
seldom should you encounter nutrient deficiency when dosing EI levels - assuming all other factors are confirmed to be good. It simply shouldn't happen, so if it does, then you know that the fault lies with some other item, typically, flow and distribution.
Again, I'm not saying that some problems can't easily be solved by adding more nutrients, but it's better to emphasize that a nutrient deficiency when dosing unlimited levels of nutrients indicates an infrastructural problem somewhere else in the tank system, in exactly the same way as occurs when we inject standard levels of CO2 and yet the plants suffer CO2 related faults while the fish suffer CO2 toxicity. So just try to be systematic and think about the other indicators in the tank. The plants, fish and the tank TELL YOU what's wrong with them, but you have to listen to them.
Search for other images of H. polysperma and see if you can compare with your plant and if the issue was discussed.
Cheers,
....one of the rarer ludwigia species.