The same question, different answers
Long sessions sometimes produce contradictory answers to the same question across turns. The model is not lying. It is responding to subtly different context — different recency, different attention sinks, different cache state. Self-disagreement is a debugging gift: it tells you which facts are not robust under context drift.
Surface, do not paper over
When you spot a contradiction, surface it explicitly: 'turn 12 you said X; turn 41 you said not-X; reconcile with sources.' Asking the model to reconcile with sources forces it to ground in something durable rather than pick the most recent answer by default.
Self-disagreement maps drift
If the same question gets different answers at turn 12, 41, and 73, you have a drift map: facts that depend on recent context, not on stable rules or sources. Move those facts to durable storage if they should be invariant; accept the variation if they are genuinely turn-specific.