don't know what your problem is but do let the pots dry out between waterings. too much water can for sure be a problem, but it may not be yours, anyway i'd let them dry and just keep watching to see what happens, not really anything you can do. how long has it been since they arrived?

I got the bamboo about 3-4 months ago.

I think you got some henon from me. What you are describing sounds more like they aren't getting enough water, as far as symptoms go, which doesn't make sense. You can let the sound dry out between waterings. The leaves will tell you when they are in need of water by starting to curl before drying up. Be careful, in dry climates like here in the southeast the time frame from leaf curl to loosing foliage and/or culm kill can be only a day or so in potted plants. But you can get an idea of the needs of your boo by letting it dry out. If you can send me some pics of your plants I can see if I can tell anything else.
Chris
dhclumber@knology.net