Whoa thats a lot of rand!!!
The guy who said that was the man who wrote the vft faq-he said that if a plant hasn't eaten a bug in like a year and it eats too many bugs it gets intergestion and dies back a bit but comes around again.
Also sometimes the process of digestion is too complex for domesticated vfts and the whole trap goes black and dies-this looks to be the case with my vft at the moment-one of it's traps that i fed looks a bit black but it could just be the fly pressing against the trap.