Knowledge retrieval on the GitHub Copilot harness suddenly slow (~1:25 min/turn)

Your trace separates the stages: SharePoint search finishes in about 11 seconds, while the remaining delay follows delivery of complete files to the GitHub Copilot harness. That makes indexing or permissions an unlikely primary cause. Microsoft documents that SharePoint knowledge can add latency, but not that every result must be read in full, so treat this as a harness behavior change or service regression until Microsoft confirms it. Compare both harnesses using the same prompt, user, sources, and file count. Then reduce the source set and temporarily remove the largest PDFs to show how latency scales. Preserve the HAR/SSE event, UTC timestamps, agent ID, environment ID, region, publication version, and exact response instruction. Check service health and republish once, but do not repeatedly rebuild the source. Open a Copilot Studio support case with the 11-second retrieval and 70-second file-reading segments; only Microsoft can confirm whether that internal instruction is intended.