shadow between displacements

[aK!]

Hello guys, i've been making a map but this weird problem bugs me at random places, there is a shadow between two displacements as you can see in the picture, I have no clue what causes this since it doesn't appear at other parts of the map where displacements are joined together. Any help is appreciated, thanks.
Tried: 1) Adding nodraw at non visible area 2) Aligning texture to be seemless 3) Remaking the entire displacement surface

[Nication]

When creating the displacement, are you selecting the entire brush or just the face that the player sees?