I had a Kenya tree that did that at night. Every night. But in the morning it would go back to normal. How long have you had it? My Kenya tree started to shed branches and then the pieces that broke off would regrow wherever they landed. This happened quite often so I got rid of it. My lfs has a tank that was completely over run by it. It's almost like a weed. Altogether they are very resilient and I would bet that it's just going through a phase.