Reading the evidence

A retry returns 200

The browser only sees the final 200. The attempts table might show a 502 followed by a 200 against another peer. That establishes multiple upstream states with those outcomes. Configured retry triggers explain which failure classes are eligible; they do not independently prove which socket operation failed.

Connect, header and response timings overlap. Do not add them into a synthetic request duration.

Buffering changes during a request

If configured response buffering is ON, effective buffering is OFF, the normalized header is no and the header is not ignored, the evidence shows the upstream header changed buffering. A streaming configuration can also disable buffering without such a header.

An upload touches disk

A nonzero temporary-file offset and disk-buffered flag establish temporary-file use. Compare observed bytes, declared length, buffer limit and maximum body size. No body contents or temporary filename is retained.

A local rejection

A 413 with declared length larger than a nonzero configured maximum is consistent with the body-size limit. No upstream attempts supports a local rejection for that request; missing attempts alone is not a universal proof of its cause.

Unknown remains unknown

Null or absent values mean unavailable or unobserved. Do not interpret them as false, zero, or a successful execution. Old schema-1 history cannot be upgraded into native evidence after the fact.