https://github.com/gamma-delta/HexMod/blob/a3b62c4ab8a653217ac5f1ea0607e7aa23e0f8b5/Common/src/main/java/at/petrak/hexcasting/api/casting/math/HexCoord.kt#L11

Per Red Blob Games, s = -q - r. The above line is missing a minus sign on this.q.

changed, thankfully it seems like s() literally isn't used anywhere so this shouldn't have been causing any issues.