u/Acceptable-Deer404

For anyone still running AdX and AdSense Backfill at the same priority level:This setup often causes random selection via Dynamic Allocation (ignoring historical CPM), which is exactly the issue the OP is facing.Google is pushing a major change in 2026:

• Phase 1 (around May 30, 2026): AdX will be prioritized over AdSense Backfill
• Phase 2 (after July 29, 2026): Full migration to AdX will be required for publishers with AdX accounts

I wrote a detailed guide in Japanese about this transition (please use browser translation when reading):【2026年5-7月必須対応】GAM＋AdX運用者向け：AdSenseバックフィルをAdXへ移行する2段階ロードマップと実践チェックリスト
https://tech-life-media.com/47.html

Background article（背景解説）:
https://tech-life-media.com/218.html

Strongly recommend moving to Yield Groups + Unified Pricing Rules instead of managing many individual Line Items.Would be great to hear how other AdOps people are preparing for these 2026 changes.