As someone who uses this plant in all 8 of my fish tanks.. This only happens when
A. you have algae growing on the leaves.
B. Too much lighting burns the leaves
Most of my tanks are simple betta tanks I don't dose anything, and I use shitty lighting and these Renekie grow really good in those tanks, but the tanks with really high lighting I noticed they tend to get some holes specially if they are closer to the lighting.
Im just telling you what I have experienced with this plant