Q.Why Is My Night Blooming Cereus Browning?
The newly sprouted pieces look burned in areas despite no direct sunlight. I don’t see any insects. What should I try?

Certified GKH Gardening Expert
Has the watering changed? Browning can indicate too much moisture in the soil or too much shade. Was the container moved to a new location?
To be on the safe side, you may want to take cuttings off the non-affected leaves and start a new plant, just in case.
https://www.gardeningknowhow.com/ornamental/cacti-succulents/night-blooming-cereus