Nepenthes dropping leaves is a common issue and can be caused by a variety of factors. Here's a detailed guide on why your Nepenthes plant may be dropping leaves and how to solve it:

1. Underwatering or overwatering: Nepenthes plants require consistently moist soil, but not waterlogged soil. If the plant is not watered enough, the leaves may wilt and drop. If the plant is overwatered, the roots can rot, which can also cause leaf drop. Check the soil moisture regularly and adjust your watering frequency as needed.

2. Low humidity: Nepenthes plants require high humidity levels to thrive. If the air is too dry, the leaves may dry out and drop. Increase the humidity by placing a tray of water near the plant or by using a humidifier.

3. Low light: Nepenthes plants require bright, indirect light to grow properly. If the plant is not receiving enough light, the leaves may yellow and drop. Move the plant to a brighter location or provide it with artificial grow lights.

4. Pests: Nepenthes plants can be affected by pests such as mealybugs and spider mites. These pests can cause leaf drop and other issues. Check the plant regularly for signs of pests and treat them promptly with an insecticidal soap or neem oil.

5. Transplant shock: If the plant has recently been repotted or moved to a new location, it may experience transplant shock, which can cause leaf drop. Give the plant some time to adjust to its new environment and avoid disturbing the roots.

6. Nutrient deficiencies: Nepenthes plants require a nutrient-poor soil, as they obtain their nutrients from insects caught in their pitcher traps. If the plant is over-fertilized, it can become too lush and the leaves may drop. Use a fertilizer specifically formulated for carnivorous plants and dilute it to half strength.

In summary, Nepenthes plants may drop leaves due to underwatering, overwatering, low humidity, low light, pests, transplant shock, or nutrient deficiencies. Identify the underlying cause of the leaf drop and take appropriate action to remedy the issue. By providing proper care, your Nepenthes plant can thrive and produce beautiful pitcher traps.