Looks like a bit of light burn, or maybe a temperature extreme? I'm not sure it's possible for that hybrid to get root rot.
I thought it might be light burn too, but that just does not add up. Having thought that earlier, I moved it to a shadier part, which had no effect. The browning even happened to leaves that were older, and were shaded by the other leaves. They died at the edges inward, while the roots rotted away. What was left of the roots smelled terrible. The stem and insides of the stem also looked discolored. I've looked for pictures that are like what I have, but nothing quite matches up. I know it's not the conditions since they were doing spectacularly until maybe at most a week ago. Inside the container, it is currently ~71 degrees. I know the relative humidity is high based on feel and the amount of condensation build up on the cover and sides of the container. I'd estimate at least 50%. Lights are 2 ft above the container, main light for the setup is a daylight white LED with a brightness of 1325 lumens. I have not taken the temperatures at night, but I doubt it drops below 60 since it is in my room. Earlier I cut up the plant after discovering the rotting root ball. I hope the cuttings take well.
I'm kicking myself a bit for not re-potting immediately after buying them.
Ps- I was pretty sure that it was a ventrata. My big ventrata is finally starting to open the first pitcher that has formed entirely during my possession of the plant. It looks great! Here's some pictures of my happier plants as well.
The house cleaners decided to stick the sick leaves I had cut off into the ventrata pot.
close up of the one of the basil shoots. Looks like it will have a cute little first pitcher soon!
some purpurea and a Scarlet Belle
the traps are looking pretty happy, with a lot of new traps forming and good coloration.
I would like to raise that nepenthes to the size of my first one, but if it dies, I guess I will learn to re-pot your plants immediately.
Thanks for all the help!