This looks like sunburn – which happens when you move an indoor plant into more direct sunlight. When the leaves aren’t used to direct sun, and suddenly they are exposed to that strong light, they burn and the leaves turn white or brown. Usually plants grow out of this once they adapt but those leaves never heal after the burn and can decline from then on.
Occasionally a plant might look sunburned when the leaves have been hit with something such as hot water, a chemical, housecleaning solutions etc. If this plant hasn’t been recently put out into the sun and you doubt that sunburn is the cause, think of what else might have hit the foliage.
Additionally, sometimes sunburn happens when windows or glass doors are suddenly at a new angle and the light reflects off of them onto a plant.