Syl's attention is firmly on the photo they're studying as they open the door to the house they share with Hal.

The first sign that something strange is going on is that suddenly they can read the Nomai writing in the picture. Not just putting together a rough meaning like they've worked up to being able to, fully comprehending it as if it was Hearthian writing. They take a couple steps before noticing the lighting is wrong. The sun was on the other side of the planet when they glanced out the window only a moment ago.