The URL alone is not the generation
Imagine a reader has the beginning of recording A cached, while the publisher replaces that URL with revised recording B. A later byte interval from B cannot safely be treated as a continuation of A merely because the address stayed the same. Container offsets may also have changed.
RFC 9110's If-Range mechanism lets a client condition a range on representation identity. A mismatch leads to the whole selected representation rather than the requested continuation. Inspect that condition before treating an unexpected full response as the only fault.
Preserve the evidence of replacement
Record the validators and lengths from the relevant responses, with observation times. A changed length is useful evidence, but equal length does not establish equal bytes. Keep release generation identifiers or controlled digests where the production workflow provides them.
Use strong validator semantics where the protocol requires them. Do not strip a weak-marker prefix and assume the result becomes suitable for If-Range. When the publisher controls the origin, review validator generation and file replacement together.
Choose a stable release model
A new versioned URL for a revised owned recording can simplify identity, cache policy and rollback. That is a publishing choice, not a requirement that every media service use the same naming pattern. The important part is a coherent promise about what a resource identity represents.
Before replacing a file in place, consider active readers and retained partial downloads. Keep the old release available for the planned handoff if the delivery design depends on it. This is an invented failure analysis, not a claim about a specific client implementation.
Questions answered
Does an unchanged URL prove unchanged media?
No. Track the selected representation's identity and publication generation.
Why might If-Range result in a full response?
If its validator does not match, the protocol avoids treating new bytes as a continuation of the old representation.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.