diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 320c312..5f1f275 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -70,6 +70,10 @@ jobs:
         with:
           go-version: ${{ matrix.go }}
           cache-dependency-path: "**/go.sum"
+          # Skip the Go cache save on Windows: the tar/zstd cache-save post-step
+          # flakes intermittently on windows-latest and fails the job even when
+          # tests pass. Linux and macOS keep caching.
+          cache: ${{ runner.os != 'Windows' }}
       - name: test -race
         working-directory: ${{ env.MODULE }}
         run: go test -race ./...
diff --git a/.github/workflows/sink.yml b/.github/workflows/sink.yml
index f421405..4539892 100644
--- a/.github/workflows/sink.yml
+++ b/.github/workflows/sink.yml
@@ -37,6 +37,10 @@ jobs:
         with:
           go-version: ${{ matrix.go }}
           cache-dependency-path: "**/go.sum"
+          # Skip the Go cache save on Windows: the tar/zstd cache-save post-step
+          # flakes intermittently on windows-latest and fails the job even when
+          # tests pass. Linux and macOS keep caching.
+          cache: ${{ runner.os != 'Windows' }}
       - name: test -race
         shell: bash
         run: |
@@ -84,6 +88,10 @@ jobs:
         with:
           go-version: "1.26.4"
           cache-dependency-path: "**/go.sum"
+          # Skip the Go cache save on Windows: the tar/zstd cache-save post-step
+          # flakes intermittently on windows-latest and fails the job even when
+          # tests pass. Linux and macOS keep caching.
+          cache: ${{ runner.os != 'Windows' }}
       - name: test -race
         shell: bash
         run: go test -C "${{ matrix.module }}" -race ./...
@@ -147,6 +155,10 @@ jobs:
         with:
           go-version: "1.26.4"
           cache-dependency-path: "**/go.sum"
+          # Skip the Go cache save on Windows: the tar/zstd cache-save post-step
+          # flakes intermittently on windows-latest and fails the job even when
+          # tests pass. Linux and macOS keep caching.
+          cache: ${{ runner.os != 'Windows' }}
       - name: integration tests
         shell: bash
         run: go test -C "${{ matrix.module }}" -tags integration ./...
diff --git a/.github/workflows/source.yml b/.github/workflows/source.yml
index ff89200..a34b00a 100644
--- a/.github/workflows/source.yml
+++ b/.github/workflows/source.yml
@@ -39,6 +39,10 @@ jobs:
         with:
           go-version: ${{ matrix.go }}
           cache-dependency-path: "**/go.sum"
+          # Skip the Go cache save on Windows: the tar/zstd cache-save post-step
+          # flakes intermittently on windows-latest and fails the job even when
+          # tests pass. Linux and macOS keep caching.
+          cache: ${{ runner.os != 'Windows' }}
       - name: test -race
         shell: bash
         run: |
@@ -73,6 +77,10 @@ jobs:
         with:
           go-version: "1.26.4"
           cache-dependency-path: "**/go.sum"
+          # Skip the Go cache save on Windows: the tar/zstd cache-save post-step
+          # flakes intermittently on windows-latest and fails the job even when
+          # tests pass. Linux and macOS keep caching.
+          cache: ${{ runner.os != 'Windows' }}
       - name: test -race
         shell: bash
         run: go test -C "${{ matrix.module }}" -race ./...
@@ -119,6 +127,10 @@ jobs:
         with:
           go-version: "1.26.4"
           cache-dependency-path: "**/go.sum"
+          # Skip the Go cache save on Windows: the tar/zstd cache-save post-step
+          # flakes intermittently on windows-latest and fails the job even when
+          # tests pass. Linux and macOS keep caching.
+          cache: ${{ runner.os != 'Windows' }}
       - name: integration tests
         shell: bash
         run: go test -C "${{ matrix.module }}" -tags integration ./...
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 4fadbed..b0ddab0 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -32,6 +32,10 @@ jobs:
         with:
           go-version: ${{ matrix.go }}
           cache-dependency-path: "**/go.sum"
+          # Skip the Go cache save on Windows: the tar/zstd cache-save post-step
+          # flakes intermittently on windows-latest and fails the job even when
+          # tests pass. Linux and macOS keep caching.
+          cache: ${{ runner.os != 'Windows' }}
       - name: test -race
         shell: bash
         run: |