The Windows binaries (and the source tarball) have been replaced with new versions because pkg-config was broken and the binaries were unusable for many use cases. There is a new 1.28.4-fixup1 tag on cerbero that includes the fix.
The hashes of the new files are:
d3c5a5bd6e89bd336341bb69b96d65eaf71326b4c332e182a15680f659119bb7 mingw/gstreamer-1.0-mingw-x86-1.28.4.exe
742e1eea05f6224bc2c10226c3fb065533ae979e09745e841a4a9cb247fc6073 gstreamer-1.0-mingw-x86_64-1.28.4.exe
6f810ad85e0fe7b566ab2f2841c0fec52e010265af6883427652e0a159a40fc7 gstreamer-1.0-msvc-arm64-1.28.4.exe
ebf1d136558bc5a90b9599095fef8db927e10978ec39bd038363d38a2debf97b gstreamer-1.0-msvc-x86-1.28.4.exe
1a745d67225e43394a4a5db929c97397cb56e74b1c38bb77c6ded4b037d3c040 gstreamer-1.0-msvc-x86_64-1.28.4.exe
2318a8998c4c2af3aff00811fcd923147d3d6ff6fbc14eea2eddf34525dbd76c cerbero-1.28.4.tar.xz
(Note that there may be a slight delay in the new files actually being served owing to the CDN setup)