Remote upload size mismatch while buffering
This wording meant bytes received while buffering a remote import did not match the expected size. It is largely a legacy map entry; current code more often says “Saved file size mismatch,” S3 upload size mismatch, or a related after-write mismatch.
Why this happens
Historically: declared length (header or init size) disagreed with bytes buffered before promote/write. Today, treat any size-mismatch family as “origin length vs bytes stored do not agree” — truncated download, bad Content-Length, or storage write drift.
Diagnose and fix
1. Compare origin Content-Length (curl -I) with the actual file size when downloaded manually.
2. Retry from a source with accurate headers; avoid HTML “download pages” that are not the raw file.
3. If storage is S3/CDN, also see S3 upload size mismatch and test credentials under Servers.
4. Check disk/space and node health if local staging is involved.