`Ash.update` unloads already loaded relationships when used in other project

[jechol]

Describe the bug
Ash.update does not unload already loaded relationships in tests within this repo (see:

ash_postgres/test/update_test.exs

Line 222 in 05f4220

test "loaded relationships remain loaded after update" do

),
but when used in another project, it does unload them unexpectedly. (See: https://github.com/jechol/ash_update_unload_check/actions/runs/14073633009/job/39412565346)

As you can see in this test file:
https://github.com/jechol/ash_update_unload_check/blob/a734f6e865e50909cb827b9d4a21815efc164e3b/test/ash_update_unload_check/content/author_test.exs#L7
the code is exactly the same as the passing test in this repo, but it fails.

To Reproduce
Clone the following repo and run mix test:
https://github.com/jechol/ash_update_unload_check

Expected behavior
The test should pass.

** Runtime

• Elixir version: 1.18.0 (same as in ash_postgres repo)
• Erlang version: 27.0.1
• OS: macOS / Ubuntu (reproduced on both)
• Ash version: main branch (4f889a2ea934abb993805059664ccf9b6e63fb10)
• any related extension versions: N/A

[zachdaniel]

The difference in the example app was that the config: default_actions_require_atomic?: true

was set, and so it was going down the atomic update path, which had a bug and was not retaining loads. Switching the action in ash_postgres test to an atomic action highlighted the issue.

[jechol]

Confirmed that it's fixed on the latest main. Thanks! 🙌
(https://github.com/jechol/ash_update_unload_check/actions/runs/14074461717/job/39414822942)