If it has been that long it sounds like phytium. Damping off but not dieing.

I'm very good at keeping one this long too. Too much wet and the roots start to rot or in my case become infected with Cyanobacteria whitch leads to root rot. Some day it might get better but I have had them lay on the cutting room floor and look the same for 2 months. Like they were preserved by imbombing fluid.

Don't waste your time start new beans or cuttings. Normally ours would be 12 to 16 inches or more by 4 weeks and ready for flower. Cutting would be 2 feet or more.

Try to let new sprouts be as dry as they can untill they get some size.