On 3 separate occasions, I have approached a ladder with my flashlight out (at the ready, turned on)

After beginnign to climb up the ladder, the flashlight suddenly turns off, the icon on my hotbar goes white, and upon reaching the top of the ladder -- the flashlight is nowhere to be found in my inventory (unless, for some reason, it has been dropped on the ground and I can't find it in the dark --- which I don't think to be the case, because I've looked extensively).