How often do you water during winter months? Do you cut the stalk off?
I'm assuming that you're using a variety of plant that is hardy in your area, and that you're leaving it in the ground over the winter. Like any other lily, once all the greenery (stalk included) has turned brown, indicating that all the nutrients have gone into the bulb, you can cut them off. The bulb has gone into dormancy, and you don't want to add any water, which risks rotting the bulbs. Here's some more information: https://www.gardeningknowhow.com/ornamental/bulbs/pineapple-lily/growing-pineapple-lilies.htm