Thanks for all the advices so far. I hope more idea will come. BTW here is my new pic of the VFT.
#1. This trap just got only 1 victim and now it's become non-reactive (a sign of dormancy).
#2-3. Slow trap and leaf development.
Upper #4. This trap got it's victim (still reactive which is the sign of the VFT not in dormancy?).
Lower VFT #4. Smaller new trap.