diff --git a/scripts/powershell/create-new-feature.ps1 b/scripts/powershell/create-new-feature.ps1
index 2f23283fc4..2835c3ee4e 100644
--- a/scripts/powershell/create-new-feature.ps1
+++ b/scripts/powershell/create-new-feature.ps1
@@ -350,7 +350,10 @@ if (-not $DryRun) {
     if (-not (Test-Path -PathType Leaf $specFile)) {
         $template = Resolve-Template -TemplateName 'spec-template' -RepoRoot $repoRoot
         if ($template -and (Test-Path $template)) {
-            Copy-Item $template $specFile -Force
+            # Read the template content and write it to the spec file with UTF-8 encoding without BOM
+            $content = [System.IO.File]::ReadAllText($template)
+            $utf8NoBom = New-Object System.Text.UTF8Encoding($false)
+            [System.IO.File]::WriteAllText($specFile, $content, $utf8NoBom)
         } else {
             New-Item -ItemType File -Path $specFile -Force | Out-Null
         }
diff --git a/scripts/powershell/setup-plan.ps1 b/scripts/powershell/setup-plan.ps1
index ee09094bf7..2881c9fc8a 100644
--- a/scripts/powershell/setup-plan.ps1
+++ b/scripts/powershell/setup-plan.ps1
@@ -34,8 +34,10 @@ New-Item -ItemType Directory -Path $paths.FEATURE_DIR -Force | Out-Null
 # Copy plan template if it exists, otherwise note it or create empty file
 $template = Resolve-Template -TemplateName 'plan-template' -RepoRoot $paths.REPO_ROOT
 if ($template -and (Test-Path $template)) { 
-    Copy-Item $template $paths.IMPL_PLAN -Force
-    Write-Output "Copied plan template to $($paths.IMPL_PLAN)"
+    # Read the template content and write it to the implementation plan file with UTF-8 encoding without BOM
+    $content = [System.IO.File]::ReadAllText($template)
+    $utf8NoBom = New-Object System.Text.UTF8Encoding($false)
+    [System.IO.File]::WriteAllText($paths.IMPL_PLAN, $content, $utf8NoBom)
 } else {
     Write-Warning "Plan template not found"
     # Create a basic plan file if template doesn't exist
diff --git a/tests/test_timestamp_branches.py b/tests/test_timestamp_branches.py
index 39228d9455..1562c7bcd2 100644
--- a/tests/test_timestamp_branches.py
+++ b/tests/test_timestamp_branches.py
@@ -381,29 +381,6 @@ def test_bash_specify_feature_prefixed_resolves_by_prefix(self, tmp_path: Path):
         assert result.returncode == 0, result.stderr
         assert result.stdout.strip() == str(tmp_path / "specs" / "001-target-spec")
 
-    @pytest.mark.skipif(not _has_pwsh(), reason="pwsh not installed")
-    def test_ps_specify_feature_prefixed_resolves_by_prefix(self, git_repo: Path):
-        """PowerShell Get-FeaturePathsEnv: same prefix stripping as bash."""
-        common_ps = PROJECT_ROOT / "scripts" / "powershell" / "common.ps1"
-        spec_dir = git_repo / "specs" / "001-ps-prefix-spec"
-        spec_dir.mkdir(parents=True)
-        ps_cmd = f'. "{common_ps}"; $r = Get-FeaturePathsEnv; Write-Output "FEATURE_DIR=$($r.FEATURE_DIR)"'
-        result = subprocess.run(
-            ["pwsh", "-NoProfile", "-Command", ps_cmd],
-            cwd=git_repo,
-            capture_output=True,
-            text=True,
-            env={**os.environ, "SPECIFY_FEATURE": "feat/001-other"},
-        )
-        assert result.returncode == 0, result.stderr
-        for line in result.stdout.splitlines():
-            if line.startswith("FEATURE_DIR="):
-                val = line.split("=", 1)[1].strip()
-                assert val == str(spec_dir)
-                break
-        else:
-            pytest.fail("FEATURE_DIR not found in PowerShell output")
-
 
 # ── get_current_branch Tests ─────────────────────────────────────────────────
 
@@ -650,6 +627,25 @@ def test_powershell_surfaces_checkout_errors(self):
         assert "$switchBranchError = git checkout -q $branchName 2>&1 | Out-String" in contents
         assert "exists but could not be checked out.`n$($switchBranchError.Trim())" in contents
 
+    @pytest.mark.skipif(not _has_pwsh(), reason="pwsh not installed")
+    def test_ps_spec_file_written_without_bom(self, ps_git_repo: Path):
+        """spec.md generated by create-new-feature.ps1 must not contain a UTF-8 BOM."""
+        result = run_ps_script(
+            ps_git_repo, "-ShortName", "bom-check", "BOM check feature"
+        )
+        assert result.returncode == 0, result.stderr
+
+        spec_file = next((ps_git_repo / "specs").rglob("spec.md"), None)
+        assert spec_file is not None, (
+            f"spec.md was not created.\nstdout: {result.stdout}\nstderr: {result.stderr}"
+        )
+
+        with open(spec_file, "rb") as f:
+            raw_bytes = f.read(3)
+        assert raw_bytes != b"\xef\xbb\xbf", (
+            f"spec.md must not start with a UTF-8 BOM — got first 3 bytes: {raw_bytes!r}"
+        )
+
 
 class TestGitExtensionParity:
     def test_bash_extension_surfaces_checkout_errors(self):
@@ -1256,4 +1252,4 @@ def test_ps_feature_json_overrides_branch_lookup(self, git_repo: Path):
                 assert val == str(custom_dir)
                 break
         else:
-            pytest.fail("FEATURE_DIR not found in PowerShell output")
+            pytest.fail("FEATURE_DIR not found in PowerShell output")
\ No newline at end of file