Functional Dependencies not working in Idris2?

flake.lock

{
  "nodes": {
    "nixpkgs": {
      "locked": {
        "lastModified": 1683777345,
        "narHash": "sha256-V2p/A4RpEGqEZussOnHYMU6XglxBJGCODdzoyvcwig8=",
        "owner": "NixOS",
        "repo": "nixpkgs",
        "rev": "635a306fc8ede2e34cb3dd0d6d0a5d49362150ed",
        "type": "github"
      },
      "original": {
        "id": "nixpkgs",
        "type": "indirect"
      }
    },
    "root": {
      "inputs": {
        "nixpkgs": "nixpkgs"
      }
    }
  },
  "root": "root",
  "version": 7
}

flake.nix

{
  description = "A very basic flake";

  outputs = { self, nixpkgs }: {
    devShells.x86_64-linux.default =
      let
        pkgs = import nixpkgs { system = "x86_64-linux"; };
      in
      pkgs.mkShell {
        buildInputs = with pkgs; [
          idris idris2
        ];
      };
  };
}

FunDep.idr

interface Custom (a : Type) (b : Type) | a where

Custom Nat Nat where
Custom Nat Bool where

f : Custom a b => a -> b -> Unit
f _ _ = ()

g : Unit
g = let x : Nat = 3
    in f x x

Running

idris --check --total --nobanner FunDep.idr

outputs

FunDep.idr:4:1-15:
  |
4 | Custom Nat Bool where
  | ~~~~~~~~~~~~~~~
Overlapping implementation: Custom Nat Nat already defined

which is (at least I think) expected behaviour.
However on idris2

idris2 --check --total --no-banner FunDep.idr

outputs

1/1: Building FunDep (FunDep.idr)

Probably expecting behaviour? I don't know.