Hmm, Im a complete newb, but maybe I can help.
There are 2 things that may help, and this helped mine when it started to do that.
Do you water your plant alot? or a little bit? It could be caused from either over watering, or under watering. If thats the case, change up your watering a little bit.
Also, this sounds stupid, but I've done it to mine. If its starting to yellow, change your watering to the opposite of what your doing now and cut a few stems off. like 2-3. What that will do is is redirect the nurtrients to the rest of the plant and give it more of a chance to survive.
Btw, a damn good looking plant in the first pic.