Why Is the Concept of “Immutability” Less Absolute on a Permissioned Chain?

Immutability is less absolute because the governing consortium or central authority on a permissioned chain retains the administrative ability to reverse or alter transactions if necessary, typically for legal or regulatory reasons. While the chain's cryptographic properties still protect against unauthorized changes, the authorized participants have the power to agree to overwrite or modify the ledger.

This flexibility is often required for compliance but fundamentally compromises the absolute, trustless immutability found in public chains.