If there's insufficient light, the
Tape grass will not thrive. This is going to result in poor growth. Fungi and bacteria can feed on the plants' tissues, which are generally common for the plants grown in shady areas.
When the plants receive too little sunlight, they tend to become spindly. They will have weaker stems because they are constantly seeking to receive light, and this can result in wilting or brown leaves. You might want to see if there are insects present or a rhizome rot in
Tape grass as this can be another sign that they are not receiving enough sunlight. If this is the case, put them in another area where they will receive bright and direct light to see if it will make a difference.