Trained on 52 Product Domains, the Earlier 51 All Regressed — A Dual-Replay Field Report on Catastrophic Forgetting in LLMs
Sequentially fine-tuned across 52 product domains, NLU F1 on earlier ones dropped 1-2 points each time (BWT -7.2). Dual-Replay — 9M adapter params + 20% dual-stream replay — pulled BWT to -4.7 (35% less forgetting), p99 under 100 ms. Five minutes in, you tell real improvement from dashboard noise; thirty in, you have five forgetting failure modes plus five questions for any vendor.
Oct 13, 2025·30 min read