I monitored these plants carefully and made sure they were separated from the others as I noticed some oddness on their leaves - thinking it was pest related I repotted them and kept them to one side to prevent the spread. Time went by and I noticed no new growth so I inspected the crowns (also known as the "heart") of the affected pinguicula and noticed a bizarre blackness - almost like it had been cut and then scorched.
I wasn't sure if it was sunburn (I'd increased watering to accommodate the increased evaporation levels and could have splashed the leaves somehow) or something else so I continued to watch carefully... I watched in horror as the leaves of the affected pinguicula began to turn brown and crispy from the crown outwards.
Pinguicula are sensitive to aerosol treatments (and I am severely athsmatic) so I did some research to look for alternative methods to cure this mystery "illness" and I didn't like what I read.
I wanted to direct all pinguicula owners in the direction of an article regarding browning heart disease. It is believed to be a combination of a fungus (known as Fusarium) and a nematode infestation... The fungus is naturally present in soil but is unable to penetrate the tissue of pinguicula... bring in the nematodes; female nematodes enter the roots of pinguicula to feed and therefore this gives the fungus a chance to attack and enter the living tissue of our plants. Death happens within a few days.
Now, I don't want all of you pinguicula owners to suddenly start panicking and thinking "OH NO WHAT AM I GONNA DO MY COLLECTION NOOOOOOO" (though I'd understand). Browning heart disease can be prevented through the use of specific fungicides and careful watering schedules. You can find the article I referred to earlier here:
Browning Heart Disease
Video courtesy of Darkrai283, thank you so much Richard - so sorry for your loss!
Red flags have gone off in my head as I noticed my young P. spec Lautner showing the same symptoms today - this happened literally overnight and this plant is in my main collection tray. Once I have repotted all my plants into individual pots I will update my website with this new information as well as adapting my recommended watering techniques and other such relevant articles.
Please be aware that watering via the tray method is still a good way to go about keeping your pinguicula with the right amount of water however if you ever notice any signs of browning heart disease please stop using the tray method immediately. Repot your plants and water from the top until you are certain that everything is all right. Sorry to be a bit of a scare-monger, that is not my intention. I wasn't aware of browning heart disease and was startled when I learned about it so I simply wanted to share my discovery to stop others from losing plants.
Edit: I've added the new information to my website and will continue to update it should I find any more information.
RNSSG: Problems & Diseases
List of online carnivorous plant suppliers