tobi/omatrack no longer exists on GitHub, so the pinned commit's archive is 404 and 1.8.6 cannot be rebuilt; the old repository host's sync deleted the published 1.8.6-1 from R2, leaving edge at 1.2.0. A public copy serves the same commit with an archive matching the pinned sha256 byte for byte. pkgrel 2 gives the rebuild a new filename, so no cache can serve the deleted 1.8.6-1 bytes for it.