Thank you, Tucker.
This particular plant had two blooming cycles on the existing spikes (over 12" long each, so definitely not a novelty species). After that, the spikes began to show signs of dying off. That's when I took to pruning them. At first, everything was fine--the cut ends dried up and the spikes remained green. But when I saw this one turn reddish then yellow/brown, I was worried that there might be something wrong, like a fungal infection.
When I pulled out the moss, some of it had a white mold on it, which I removed. The rest of the moss seemed fine, so I reused it because I didn't have any moss on hand. I did buy some new moss when I repotted my other plants... I've been thinking that maybe I should refresh the moss on this one, just in case. What do you think?