My VFT has at least one trap closed EVERTIME 24/7
I don't think it's overfeeding if half the traps are closed, though since your house has many insects, it's best to let ur VFT catch every insect on it's own.
How long have you had your VFT? Strangely, when I transfered my VFT from my condominium to my landed house last month(when I moved in), my VFT traps became smaller and smaller until they were only 3/4 of the original trap size. But they were catching TONS of flies, more than half my traps were constantly closed the first two weeks. Just sharing my VFT's condition......
My advice? If your VFT is growing fast (aka putting out lots of traps in a short period), you shouldn't worry. VFT's will lose their traps more often, but if they lose more than they can replace, thats a problem worth noting(such as only 3-4 traps left). Smaller trap also occurs when you put the VFT's under stronger light, but usually only momentarily as they adapt. As long as your VFT isn't deformed, getting super small
or experiencing fungus attack and diseases, I woudn't worry. They are quite hardy CPs