Ok, so your material is basically snow.
which could mean that your specularity and roughness are off in the landscape material.
The reason for them looking different is the light angle if you are dealing with the normal. (And time of day in the shots).
First, make sure your normal file has appropriate values.
second, make sure you aren’t multiplying it above or below 0 to 1 range in your instance. (You could also clamp before the final output).
Second, check that you have at least a scalar plugged in, to control specularity and roughness.
Make sure nothing is plugged into emissive too. Your first shot is a night scene. Why is the ground so bright if light is set correctly? (Also, Remeber that the skylight works at night and that the intensity should be manually changed if using a cycle system or else it would look like it does at daytime).
Once you have that sorted you can play with the material instance to check what results the specular/roughness changes give to the time of day and light angle you are playing in. Maybe you can even scale down the normal’s intensity a bit to have a more pleasant result.
Given the fact one picture is night and the last picture is day, there’s a decent chanche the material is supposed to look different, and that it would look different in editor too if the light angle were to match (The angle of the light during nighttime is under the landscape usually, leaving only the skylight to light the area unless a moon light source is introduced).