The argument
Your Diagram Is Not Wrong. It Is From a Different Timeline.
A diagram remains useful only while its systems, relationships, trust boundaries, and ownership claims can be reconciled with current authoritative sources.
The field pattern
The network diagram still shows the old ingress path. The data-flow diagram includes the new processor but not its administrative plane. The inventory knows about both, and the firewall knows about three more paths nobody drew. Every artifact is recognizable. None can tell the whole current story.
Why it matters
Diagram Drift weakens every conclusion that depends on the drawing. Scope, segmentation, data flow, responsibility, and sampling decisions may each be reasonable in isolation yet anchored to a model that no longer matches the environment.
The cure is not a more beautiful diagram. It is a maintained relationship between the diagram and authoritative inventories, configurations, change records, and named owners, with differences treated as actionable signals.
Questions that expose the Wack
- When was each relationship on this diagram last reconciled to an authoritative source?
- Which control-plane and security-service paths are absent from the business data flow?
- What production changes require the diagram owner to review or update it?
- Which artifact wins when the diagram, inventory, and configuration disagree?