BTW, the name is actually,
P. 'Weser'. It is one of the first registered cultivars in the genus.
If you're giving it the conditions you describe, you may need to start feeding it, too. They do well with a little spritz of dilute soluble balanced fertilizer solution, sprayed on their leaves, regularly (about once or twice per week). Additionally, adding a light dusting of dried/powdered insects, or high protein fish food, once per week, is also beneficial. If you're already feeding them, but just didn't think to mention it, take this as additional feeding guidance.
Some may argue that without summer leaves, they can't assimilate much nutrients, but they do have roots, too. They don't only absorb nutrients through their leaves, but use those roots to good effect, as well.
Additionally, you didn't mention how close you have you plants, to the lights. Within six inches would be my recommendation. Also, I prefer to keep mine virtually floating in water.
And you may wish to check out this thread,
Cultivating Mexican Pinguicula.