Create a new material using substrate, assign it to a mesh. Enable refraction. Set blend mode to any of the translucents or additive. During a level sequence animation, that mesh will glow green where it tries to refract. Even if you disconnect the refraction node, or set the refraction node to a 0 parameter, the glow occurs. Only when you set refraction to none will the glow stop.
In this case, the center [black] material has refraction enabled. Its black because all the nodes are disconnected [surface, refraction, etc]. The sides meshes are using megascans copper, but even with the default worldgridmaterial, the behaviour is the same.
Here is another animation, with the center material applied as intended.
Is this because substrate is experimental, or can a change in a setting somewhere fix the glow anomoly during refraction?