Description:
Summary

When creating an accessible tagged PDF from InDesign, the reading order of elements in the exported PDF becomes unstable and incorrect whenever new elements are added to an existing document. The only reliable workaround is to rebuild the document from scratch with elements placed in the correct reading order from the beginning.

Steps to reproduce

1. Create an InDesign document with interactive form fields (text inputs and checkboxes).
2. Set the reading order using the Articles panel ("Use for PDF tagging order").
3. Export to tagged PDF and verify reading order with a screen reader — order is correct.
4. Add new elements (e.g. additional checkboxes or text frames) to the existing document.
5. Export again and test with a screen reader.

Expected behavior

The reading order should remain consistent and follow the Articles panel order, even after new elements are added.
Actual behavior

InDesign appears to apply a mix of element creation order, Articles panel order, and Tab order (keyboard navigation), producing an unpredictable result in the exported PDF. In our case, the screen reader jumped from form fields to the logo and protocol number before returning to the correct sequence.

Workaround

Create a new blank InDesign document and paste all elements in the correct reading order. This produces a correct result, but the fix must be reapplied every time structural changes are made to the document.
Environment

Version Adobe InDesign: 2026
Verified with: screen reader testing conducted with a blind user using JAWS and NVDA; also verified via Adobe Acrobat accessibility checker and keyboard navigation (Tab key).

Impact

This issue significantly affects accessible PDF production workflows. Any document update requires a full rebuild of element order, which is not sustainable for documents that undergo frequent revisions.