Ash 3.4 Migration Error: (Protocol.UndefinedError) protocol Enumerable not implemented for false of type Atom

I’m working with the realworld demo, and I’m trying to add a table using mix codegen or mix ash_postgres.generate_migrations, but each gives me the error:

Compiling 1 file (.ex)                                                                                                                                                                 │
Getting extensions in current project...                                                                                                                                               │
Running codegen for AshPostgres.DataLayer...                                                                                                                                           │
** (Protocol.UndefinedError) protocol Enumerable not implemented for false of type Atom. This protocol is implemented for the following type(s): DBConnection.PrepareStream, DBConnecti│
on.Stream, Date.Range, Ecto.Adapters.SQL.Stream, File.Stream, Function, GenEvent.Stream, HashDict, HashSet, IO.Stream, Iter, Jason.OrderedObject, List, Map, MapSet, Phoenix.LiveView.L│
iveStream, Postgrex.Stream, Range, Rewrite, Stream, StreamData                                                                                                                         │
    (elixir 1.16.2) lib/enum.ex:1: Enumerable.impl_for!/1                                                                                                                              │
    (elixir 1.16.2) lib/enum.ex:194: Enumerable.member?/2                                                                                                                              │
    (elixir 1.16.2) lib/enum.ex:2006: Enum.member?/2                                                                                                                                   │
    (elixir 1.16.2) lib/enum.ex:4402: Enum.reject_list/2                                                                                                                               │
    (ash_postgres 2.1.19) lib/migration_generator/migration_generator.ex:2892: AshPostgres.MigrationGenerator.identities/1                                                             │
    (ash_postgres 2.1.19) lib/migration_generator/migration_generator.ex:2603: AshPostgres.MigrationGenerator.do_snapshot/3                                                            │
    (ash_postgres 2.1.19) lib/migration_generator/migration_generator.ex:2596: AshPostgres.MigrationGenerator.get_snapshots/2                                                          │
    (elixir 1.16.2) lib/enum.ex:4326: Enum.flat_map_list/2

I have no idea where to start debugging this, but have found this topic that looks slimilar: AshGraphql Errors Encountered During Ash 3.0 Migration

From my mix.exs

elixir: "~> 1.16.2",
...
:phoenix, "~> 1.7.14",
:ash, "~> 3.4",
:ash_postgres, "~> 2.1"

Any help is appreciated, thanks.