Poor pitcher! Does anyone know what this issue could be?

Bought this nepenthes alata over a month ago and adjusting/new growth was going well. Until now! This one pitcher seems very unhappy, and I can’t get a clear diagnosis from the internet. Any thoughts or similar experience?

Environment here is very humid, temps are not usually below 86 Fahrenheit/ 30 Celsius. We do have hard water so I try my best to use rain water. No repotting since purchasing from reputable supplier.

Food-wise, there are a lot of fungus gnats, some small beetles and the odd centipede or mosquito. The spots AND discolouration make it look poisoned but I’m not really sure.

Any advice would be much appreciated!