The configured URL

    http://wrongsideofmemphis.wordpress.com/feed/atom/?tag=english+python

redirects three times to https://wrongsideofmemphis.com/feed/atom/?tag=english+python,
which WordPress.com has been serving from a pinned edge-cache entry
(x-nc: HIT, last-modified: Sat, 16 Aug 2025) for close to a year. The
newest post in that response is "Agents and Agency" from 2025-08-10, and
conditional requests against it return 304, so Channel.update() logs
"Feed unchanged" indefinitely and no new posts ever reach the planet.

The origin itself is fine -- the same URL with a cache-busting parameter
returns current content -- so only that one cache key is stuck.

Switch to the tag-permalink form, which serves fresh content and keeps
the identical english AND python filter. Verified to return the same
post set plus everything published since August 2025, and to still
exclude posts tagged english but not python. Validates as Atom 1.0.

The new URL also drops the redirect chain and starts on a fresh planet
cache key, discarding the stored etag/modified that was pinning fetches
to a 304.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>