It seems like if you gain some vertical distance from a reflective surface, the reflections get offset in opposite direction to the point they appear disconnected. I've provided a couple screenshots to show the issue (first one shows them looking normal when you're close to water, and second shows the offset look when viewed from a high vertical distance).

I understand. I suppose you're using Distant Horizons, or if not, you're using a large draw distance.

Every reflection is a trick. In the close range, a screen space reflection is used... up to a certain distance. Since the position of objects doesn't change much if they're very far away, there's no need to extend path tracing too far for performance reasons.

For the terrain rendered by Distant Horizons, the reflection is simply a flip of the screen image, which makes it less accurate.

It's not the height, as you suggest—it's simply the distance to the reflection point.

Everything is done for performance. Anything else would make reflections more expensive, which goes against the shader's philosophy.