Did you change its growing conditions? I recall you stated earlier that you fed them, how did you feed them exactly? If you are using artificial food like fish pellets and don't control the amount you give them, it can do more harm than good. Dry fish pellets also take a lot more effort for the plants as they have to use up their dew to first get the pellets moist before drawing out the nutrients.
What I do is crush the betta pellets and mix with some water. I use a sewing needle as a spoon of sorts and scoop up the food in the needle's threading hole and brush it onto the dew threads. This method seems to allow most of my sundews to completely consume the food in a few days and reset for more.
FWIW, the capensis I feed are probably 10 times the size of the ones from the same seedling batch that I have not. I also grow my capensis much more on the wet side as they have done best with those conditions, however, I keep all my dews on the slightly lower humidity side so YMMV.