You are using VK carts right? I am guessing that you are at a point where you have refilled all your carts for around 4-5 days now? Maybe more? For sure the VK carts take a lot more than just a few drops to refill!! I give mine at least 10 drops! If these are overfilled, the excess will just run out. Let us know what day you think the carts are on, this is probably the issue. Yes, you can refill these carts, but I have noticed that the older they get, the harder the draw and the hotter it runs after refilling. I have found that right after refilling, the draw can be extremely hard and the cart gets quite hot. I just keep vaping, taking enough breaks that I won't start a fire

(letting it cool down), then usually, after awhile, it gets settled back in and vapes like a dream again, not like a new cart but still quite nice. The older the cart gets the longer it takes to get it settled back in and for the draw to lighten up some and the cart to stop getting as hot. I am guessing that you have circulated your carts and they are all at the same stage/age now? Maybe it is the heat that eventually kills these disposables if you keep them going? These were meant for single usage, though I can't see tossing a unit that still works

If you have used a 901 and have refilled many times, you see that the filling loses its ability to absorb, that is when you either get a new cart or put in new filling. With the VK I am sure the same thing happens, the filler just doesn't absorb and distribute the way it did at first because the heat has messed with the fibers. I have used these carts up to 6 days, but by the 5th to 6th day, they get pretty fussy. I have found that overfilling the cart until I have some coming out the other end, then letting it sit for at least 10 minutes so any excess drains off, then vaping again usually will get it working ok. It will run hot for a while, but adding a couple more drops after some good hits, will usually get it vaping well again, not running so hot that you kill any flavor and not having to draw so hard. When any of these run really hot, they burn thru the juice like crazy, so remember to keep up with the replacement. Hope this has helped.