We've noticed that some % of upstream packets going to from our office wifi to Cloudflare are partially replaced by all 0-bytes. This happens above the network layer because the TCP checksum is correct.
We typically observe this as https uploads failing with "bad record mac", but we can reproduce the exact corruption pattern using a public echo server.
We are not the only people with this problem: Xfinity forum, March 2026 · Xfinity forum, July 2026 · Efpophis gist