Frustrating Bug

Codex Windows build 26.901.5280.0 has a reproducible account-change history and sidebar-state bug. Since maybe 1 month, changing the account causes the newest 1–3 days of chats to disappear while older chats remain visible. Local Codex session JSONL files and state_5.sqlite still contain recent threads, so the issue appears to be a history projection/reconciliation problem rather than deletion.
The same issue affects sidebar custom sections. I had a UO People section containing 4 projects and an AlmaBetter section containing 6 projects. These 10 project assignments were restored successfully, but after another account change the active sidebar state showed both sections empty. Older populated section records still exist locally, while the new active account-state record contains the same sections with zero items.
Suspected areas: authentication-context change, paginated thread history projection, local/server reconciliation, and account-keyed custom sidebar state. Please investigate why recent paginated threads and sidebar project memberships are dropped or replaced after account changes.

Reproduce the account change with the local Codex session JSONL files and state_5.sqlite as evidence, then inspect the authentication-context, paginated thread history, reconciliation, and account-keyed sidebar state paths. Done means recent chats remain visible and restored custom sidebar sections retain their project memberships after an account change.