Problem Description

An error occurs when a user attempts to use a form that includes a question with both last-saved and external choices loaded by the search() function.

Steps to Reproduce

1. Open the attached form: lastSavedForm.zip
2. Select any answer and save the form.
3. Open the blank form again.

Expected Behavior

The form should open without errors and function as expected.

Additional Details

The problem has been reported on the forum: https://forum.getodk.org/t/last-saved-function-error-in-v2025-2-0-collect/55622

While the underlying issue is not new, it has become more noticeable after merging this pull request: #6696

I was also able to reproduce a similar issue in older versions of the app using a slightly modified form. Although the error message appears different, the root cause remains the same.

1. Open the attached form: lastSavedInFieldListForm.zip
2. Select any answer and change it.