diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index e323e618e8..87eaa51632 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -605,8 +605,15 @@ jobs:
         # Normalize file modification timestamps so that go test can use the
         # cache from the previous CI run. See https://github.com/golang/go/issues/58571
         # for more details.
+        #
+        # mtimehash only optimizes cache hits, so a missing binary must not
+        # fail the job before any tests run (coder/internal#1630).
         run: |
-          find . -type f ! -path ./.git/\*\* | mtimehash
+          if command -v mtimehash >/dev/null 2>&1; then
+            find . -type f ! -path ./.git/\*\* | mtimehash
+          else
+            echo "::warning::mtimehash not found; skipping file timestamp normalization (Go test cache may be cold)"
+          fi
           find . -type d ! -path ./.git/\*\* -exec touch -t 200601010000 {} +
 
       - name: Normalize Terraform Path for Caching
diff --git a/.github/workflows/nightly-gauntlet.yaml b/.github/workflows/nightly-gauntlet.yaml
index 0fd61bb9a2..9ca10e1bd0 100644
--- a/.github/workflows/nightly-gauntlet.yaml
+++ b/.github/workflows/nightly-gauntlet.yaml
@@ -68,6 +68,11 @@ jobs:
           install-args: "go terraform"
 
       - name: Install Go mise tools
+        # retry.sh is a bash script, so an explicit shell is required for the
+        # Windows matrix entry. Under the default PowerShell shell the step
+        # reports success without running the install, so gotestsum is
+        # silently missing whenever the mise cache misses (coder/internal#1630).
+        shell: bash
         run: ./.github/scripts/retry.sh -- mise install --locked go:gotest.tools/gotestsum
 
       - name: Setup Embedded Postgres Cache Paths