Error initializing thaw

[dafitt]

I get an error when running thaw with the --init flag. Output of thaw --init --dry-run -vvv:

   DEBUG  Thaw { args={ _=[  ] "--init"=true "--dry-run"=true "--verbose"=3 } }
   INFO   Thaw Dry run enabled. No changes will be made.
 ﯎  TRACE  Thaw Processing input nixpkgs...
   ERROR  Thaw An unexpected error occurred.
14 |         return version
15 |       } else {
16 |         version = version.version
17 |       }
18 |     } else if (typeof version !== 'string') {
19 |       throw new TypeError(`Invalid version. Must be a string. Got type "${typeof version}".`)
                ^
TypeError: Invalid version. Must be a string. Got type "object".
      at new SemVer (/home/david/.local/cache/.bun/install/cache/semver@7.6.0/classes/semver.js:19:12)
      at parse (/home/david/.local/cache/.bun/install/cache/semver@7.6.0/functions/parse.js:7:11)
      at diff (/home/david/.local/cache/.bun/install/cache/semver@7.6.0/functions/diff.js:5:13)
      at /nix/store/cfiaak0g6k8xpk0fb74j9j6a2py7zyn6-src/util/forge.ts:44:17
      at reduce (:1:20)
      at /nix/store/cfiaak0g6k8xpk0fb74j9j6a2py7zyn6-src/util/forge.ts:43:15
      at processTicksAndRejections (:61:76)

My flake.nix inputs look like this:

inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
    snowfall-lib = { url = "github:snowfallorg/lib/dev"; inputs.nixpkgs.follows = "nixpkgs"; };
    snowfall-thaw = { url = "github:snowfallorg/thaw"; inputs.nixpkgs.follows = "nixpkgs"; };
};