This can happen when a small phone flash is too weak to properly light the subject at that distance. The flash still creates an eye reflection, but the camera may also raise ISO/exposure to compensate for the ambient light, which can blow out the usual red-eye into a pale silver or white-looking reflection. A bright object in the scene could also affect metering and make this more likely.

You didn’t necessarily do anything unusual—it's a limitation of small built-in flashes.

For repair, automatic red-eye tools may fail because the eyes aren’t red enough to detect. You don’t need full Photoshop; a basic editor like GIMP should work. Zoom in, select the pupil area, and darken it manually with a small brush or a burn tool. Just keep the edit subtle so the pupils still look natural.