Should not other plant species be giving him more issues than the Anubias if nutrient toxicities are the issue here?
On another note, kinda curios. How do you dose your tank, do you dose everything separately? You are on a lot about ratios and it seems to me that you think all (to this date) versions of micro blends, be it dry mixed or premixed are in ratios making them toxic to some extent? How do you combat this yourself. Do you have any recent pics of your tank? Your plants must look stunning considering the amount of precision you must apply when running your tank, sounds like a full time job tbh.
I'd need close-up pics of the other plants to determine if there are issues, but from far away, there are some growth patterns that look characteristic of EI dosing.
I'm still doing exploratory experiments to observe plant response to certain individual nutrients. So far, it's become apparent that it's very difficult to grow some very sensitive species alongside ones that have higher nutrient demands. Growing the sensitive species well resulted in nutrient deficiencies in others. Growing the higher nutrient demand plants results in toxicities of the sensitive species. Some of the plants grow very healthy until I change the dosing. I haven't yet been able to find a balance that suits all plants in my tank.
The only thing I know with high certainty is that a well developed root system is vital for plant health since it can acquire necessary nutrients in the substrate which may not be present in enough quantities in the water column.
In the pic below, the Rotala "Bangladesh" that had been trimmed and replanted in sand suffers from small new leaves as a result of a micronutrient deficiency while the stems that are still rooted in the Floramax substrate (above it in the pic) are still nice and full.
Here's how the same R. "Bangladesh" looked right after trimming and replanting:
So you can see that the stems were initially healthy when trimmed but due to low micronutrients in the water column, suffered from deficiencies and was not able to acquire any from the inert sand substrate.
I spend far less time observing and working on the tank than when I was dosing EI and had dozens of problems that could not be resolved no matter what I did. I actually have hours of free time each day to spend on my art which i didnt have when i was dosing EI. I no longer need to scrub the algae off the walls each week nor do i need to do weekly water changes or trimmings. However, I will do more water changes when it becomes obvious that I OD'd on a certain nutrient. The main question i ask myself now is "what deficiency am i observing?", which can actually be answered, rather than "what the f*** is wrong?" and have no idea what the answer is.
It's also becoming apparent that it's probably better to dose a comprehensive micronutrient fertilizer and adjust individual ratios than to dose individual micronutrients since it can quickly lead to nutrient imbalances.