RAG Serves the Superseded Value 36-38% of the Time on Real GitHub Fixes; a Supersession Memory Drives It to Zero

arXiv 2608.20685·medium signalXBlueskyLinkedInCopy link

Temporal Validity on Real Software Histories (arXiv 2608.20685, Aug 21) extracts 130 clean atomic state transitions from 707 real GitHub issues in SWE-bench Lite and Verified, where a fix changes one identifiable value and the stale and current statements differ only in that value. Plain RAG scores 0.57-0.59 answer accuracy and, when forced to answer, returns the superseded value 36-38% of the time, with an LLM reranker failing to help while adding latency (~18s versus ~2.1s). A deterministic (subject, relation, object) supersession memory called MemStrata reaches 0.91 accuracy at RAG latency. The authors are explicit that only ~18% of real fixes are clean atomic transitions.