diff --git a/internal/services/submission_md.go b/internal/services/submission_md.go
index 3d155f7..e64efd8 100644
--- a/internal/services/submission_md.go
+++ b/internal/services/submission_md.go
@@ -405,6 +405,23 @@ func parseInlineSpans(text string) []inlineSpan {
 	i := 0
 	n := len(text)
 	for i < n {
+		// Preserve {{...}} placeholders verbatim. Underscores and
+		// other Markdown-significant chars inside a placeholder key
+		// (e.g. {{project.case_number}}) must not be interpreted as
+		// bold/italic delimiters — otherwise the key gets stripped of
+		// its underscores and the v1 placeholder pass looks up the
+		// wrong key, surfacing [KEIN WERT: project.casenumber] in the
+		// preview.
+		if i+1 < n && text[i] == '{' && text[i+1] == '{' {
+			rel := strings.Index(text[i+2:], "}}")
+			if rel >= 0 {
+				end := i + 2 + rel + 2
+				cur.WriteString(text[i:end])
+				i = end
+				continue
+			}
+			// Unmatched {{ — fall through to plain character handling.
+		}
 		// Bold delimiters first (longer match wins over italic).
 		if i+1 < n && (text[i:i+2] == "**" || text[i:i+2] == "__") {
 			flush()
diff --git a/internal/services/submission_md_test.go b/internal/services/submission_md_test.go
index b85b73c..b77ca4b 100644
--- a/internal/services/submission_md_test.go
+++ b/internal/services/submission_md_test.go
@@ -86,6 +86,90 @@ func TestRenderMarkdownToOOXML_PlaceholdersPassThrough(t *testing.T) {
 	}
 }
 
+func TestRenderMarkdownToOOXML_PlaceholderUnderscoresPreserved(t *testing.T) {
+	// Regression: a placeholder key containing underscores (project.case_number,
+	// user.display_name, project.patent_number_upc) used to get its underscores
+	// consumed by the italic/bold inline scanner — the OOXML stored
+	// {{project.casenumber}} and the preview surfaced
+	// [KEIN WERT: project.casenumber] instead of the real value.
+	cases := []string{
+		"{{project.case_number}}",
+		"{{user.display_name}}",
+		"{{project.patent_number_upc}}",
+		"prefix {{project.case_number}} suffix",
+		"two: {{a.b_c}} and {{d.e_f}}",
+		"mixed: _italic_ then {{project.case_number}} then __bold__",
+	}
+	for _, in := range cases {
+		out := RenderMarkdownToOOXML(in, "Normal")
+		// Every placeholder substring in the input must appear verbatim
+		// in the output (XML escaping is irrelevant for {} and _).
+		for _, ph := range extractPlaceholders(in) {
+			if !strings.Contains(out, ph) {
+				t.Errorf("input %q: placeholder %q lost; got %q", in, ph, out)
+			}
+		}
+	}
+}
+
+func TestParseInlineSpans_PlaceholderWithUnderscoresIsLiteral(t *testing.T) {
+	// Direct guard on the inline scanner. {{project.case_number}} must
+	// emit as a single non-italic span containing the full placeholder.
+	spans := parseInlineSpans("{{project.case_number}}")
+	if len(spans) != 1 {
+		t.Fatalf("expected 1 span; got %d (%+v)", len(spans), spans)
+	}
+	if spans[0].Italic || spans[0].Bold {
+		t.Errorf("placeholder must not be italic/bold; got %+v", spans[0])
+	}
+	if spans[0].Text != "{{project.case_number}}" {
+		t.Errorf("placeholder text corrupted: got %q", spans[0].Text)
+	}
+}
+
+func TestParseInlineSpans_ItalicAroundPlaceholder(t *testing.T) {
+	// Italic delimiters outside a placeholder still work; the placeholder
+	// itself stays literal even when it sits between italics.
+	spans := parseInlineSpans("_before_ {{x.y_z}} _after_")
+	var saw struct {
+		italicBefore bool
+		placeholder  bool
+		italicAfter  bool
+	}
+	for _, s := range spans {
+		if s.Italic && s.Text == "before" {
+			saw.italicBefore = true
+		}
+		if !s.Italic && !s.Bold && strings.Contains(s.Text, "{{x.y_z}}") {
+			saw.placeholder = true
+		}
+		if s.Italic && s.Text == "after" {
+			saw.italicAfter = true
+		}
+	}
+	if !saw.italicBefore || !saw.placeholder || !saw.italicAfter {
+		t.Errorf("expected italic/placeholder/italic structure; got %+v", spans)
+	}
+}
+
+// extractPlaceholders pulls every {{...}} occurrence out of a Markdown
+// source. Tiny helper, only used by the regression test above.
+func extractPlaceholders(s string) []string {
+	var out []string
+	for {
+		start := strings.Index(s, "{{")
+		if start < 0 {
+			return out
+		}
+		end := strings.Index(s[start+2:], "}}")
+		if end < 0 {
+			return out
+		}
+		out = append(out, s[start:start+2+end+2])
+		s = s[start+2+end+2:]
+	}
+}
+
 func TestRenderMarkdownToOOXML_XMLEscape(t *testing.T) {
 	out := RenderMarkdownToOOXML("a & b < c > d", "")
 	if strings.Contains(out, " & ") {