1.20.8 fails checksum, refuses to install via Homebrew

Tried upgrading, and got this error:

brew upgrade
==> Casks with 'auto_updates true' or 'version :latest' will not be upgraded; pass `--greedy` to upgrade them.
==> Fetching downloads for: mochi
✘ Cask mochi (1.20.8)                                                                                                                                                   Verifying   138.4MB/138.4MB
Error: Cask reports different checksum:     989ecbc36bd5da9ed065584b3eb46666cad808d64d4215fa585cf1931e0cb580
       SHA-256 checksum of downloaded file: 92afffd256d47e6ec62b4241d0b70081f6d3b48a41a4510b469ac982a3cdb7b3
==> Upgrading 1 outdated package:
mochi 1.20.7 -> 1.20.8
==> Upgrading mochi
==> Purging files for version 1.20.8 of Cask mochi
Error: mochi: SHA-256 mismatch
Expected: 989ecbc36bd5da9ed065584b3eb46666cad808d64d4215fa585cf1931e0cb580
  Actual: 92afffd256d47e6ec62b4241d0b70081f6d3b48a41a4510b469ac982a3cdb7b3
    File: /Users/matthew/Library/Caches/Homebrew/downloads/6e2981eb9b9126695abbcb1bdd35da079832e817f81e722b2776b85313e6b7e5--Mochi-1.20.8.dmg
To retry an incomplete download, remove the file above.

Just in case the file was genuinely corrupted, I deleted it and tried again, but got the same error.