Additive-blend + refraction breaks

Godot Version

v4.2.1.stable.official [b09f793f5]

Question

Hi all,

I am trying to create a sort of glass-orb with another object inside of it.
As you can see in the video, when I move outside of the orb, the object disappears.

The glass material is refractive and transparent. Enabling refraction specifically seems to break things.
The other object is a simple gdshader with the following render_modes: blend_add, unshaded

Any ideas as to how I might fix this?

Thank you!