Not enough light

What's happening

Marble Queen carries some of the heaviest variegation of any pothos, and the creamy-white patches have no chlorophyll. In dim conditions the plant can't make enough energy from its limited green tissue, so new leaves come in greener and greener to capture what little light there is. Low light also stretches the vines toward the window, leaving long gaps between small leaves — a habit called legginess.

How to fix it

Move the plant to a brighter spot with plenty of bright, indirect light — a few feet back from an east or north window, or filtered south/west light. Because this variety needs more light than green pothos just to hold its pattern, a genuinely dim room usually calls for a full-spectrum grow light, which is often the only way to bring the marbling back. Already-greened leaves stay green, but new growth in better light returns crisply variegated and compact.

This is general guidance based on common symptoms; individual plants vary.