Indesign Page Master (Left Side Overflow, RIght SIde Image)

I am trying to set up a book layout in InDesign (2025) with the following requirements:

1. Document Setup:

   • Facing Pages enabled.
   • Left pages are for flowing text, using a Primary Text Frame.
   • Right pages are for static images, with no text frames or threading.

2. Expected Behavior:

   • When I place text on the first left-side page, it should overflow into new left-side pages automatically.
   • InDesign should create additional left-side pages and thread the text into their Primary Text Frames without any manual intervention.

3. Current Problem:

   • I have set up the text frame on the left Parent Page as a Primary Text Frame.
   • Smart Text Reflow is enabled with the following settings:
     • Limit to Primary Text Frames checked.
     • Add Pages set to "At End of Story."
   • Despite this setup, when I place text, it overflows into a red + sign and does not automatically create or flow into new left-side pages.
   • To thread text into subsequent left-side pages, I must manually click the out port of each text frame and connect it to the next page, which is impractical for a 500+ page book.

4. What I’ve Tried:

   • Confirmed the left-side text frame on the Parent Page is designated as a Primary Text Frame.
   • Verified that Smart Text Reflow is enabled and properly configured.
   • Ensured no text frame exists on the right-side Parent Page.
   • Checked that all document pages inherit the correct Parent Page (A-Master).
   • Tested threading the Parent Page’s text frame manually via the out port (which either creates additional frames or does nothing for document-level auto-threading).

5. Key Question:

   • How do I configure InDesign to automatically create and thread text into new left-side pages when the text overflows without manual threading?

Any guidance or clarification on what I may be missing in my setup would be greatly appreciated.