I have nbc for many years. It developed holes …
It starts as web like coverings on top of leaf then finally a hole in the leaf???
Certified GKH Gardening Expert
This is a fungal infection. This is usually caused by the soil remaining too wet for too long. It can be treated easily, but it will be best to maintain the plant properly to avoid future infection.
The next time that you water it, just replace 1/4 of that with peroxide. Water this in once, and it will kill off the infection. You may notice a little damage from the treatment, but it will be followed by aggressive growth.
This article will give you more information on the care of these: https://www.gardeningknowhow.com/ornamental/cacti-succulents/night-blooming-cereus/night-blooming-cereus.htm