diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index e8f50b50..a390df24 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -91,7 +91,8 @@ jobs:
         # due to https://github.com/google/google-java-format/issues/1072.
         os: [ubuntu-20.04, macos-latest, windows-latest]
     env:
-      SUFFIX: ${{fromJson('{"ubuntu-latest":"linux-x86-64", "macos-latest":"darwin-arm64", "windows-latest":"windows-x86-64"}')[matrix.os]}}
+        # NB: Must keep the keys in this inline JSON below in line with the os: above!
+      SUFFIX: ${{fromJson('{"ubuntu-20.04":"linux-x86-64", "macos-latest":"darwin-arm64", "windows-latest":"windows-x86-64"}')[matrix.os]}}
       EXTENSION: ${{ matrix.os == 'windows-latest' && '.exe' || '' }}
     steps:
       - name: "Check out repository"