Revision
A change to a previously published data point after new information arrives or a calculation is corrected.
Revisions have ordinary causes: a chain reorganization invalidates recent blocks, an indexer bug is fixed, a wallet is relabeled or a new exchange wallet is discovered, a supply schedule turns out to have been misread, or a venue is dropped for suspected wash trading. The practical effect is that a chart captured today may not match the same chart next month, even though the underlying blockchain is immutable. Research practice is to snapshot the data used, record the retrieval timestamp, and re-run analyses against the current vintage before publishing conclusions. Unlike official economic statistics, most digital-asset providers publish no revision calendar and often no notice at all.
In practice
Adding a newly identified exchange wallet to a label set changes every historical netflow figure that wallet touched.
The common misunderstanding
Blockchain data being immutable does not make published metrics immutable; the derived series built on top of the chain are revised regularly.