diff --git a/src/cli/completions/sources/spark-tables.ts b/src/cli/completions/sources/spark-tables.ts
index a47bf0b..ebfc26d 100644
--- a/src/cli/completions/sources/spark-tables.ts
+++ b/src/cli/completions/sources/spark-tables.ts
@@ -25,11 +25,14 @@ export const sparkTablesSource: CompletionSource = {
 
   scan(index) {
     const items: SparkTableCompletion[] = [];
-    const slugger = new Slugger();
 
     for (const [filePath, content] of Object.entries(index)) {
       if (!filePath.endsWith(".md")) continue;
 
+      // Fresh slugger per file so duplicate headers across files don't
+      // pollute each other.  (github-slugger is stateful.)
+      const slugger = new Slugger();
+
       const lines = content.split(/\r?\n/);
       for (let i = 0; i < lines.length; i++) {
         const headerCells = splitTableRow(lines[i]);
diff --git a/src/components/journal/completions.ts b/src/components/journal/completions.ts
index c719a7f..8029424 100644
--- a/src/components/journal/completions.ts
+++ b/src/components/journal/completions.ts
@@ -81,12 +81,15 @@ async function scanClientSide(): Promise<JournalCompletions> {
   const links: LinkCompletion[] = [];
   const sparkTables: SparkTableCompletion[] = [];
   const tagRegex = /<md-dice[^>]*>\s*([\s\S]*?)\s*<\/md-dice>/gi;
-  const slugger = new Slugger();
 
   for (const filePath of paths) {
     const content = await getIndexedData(filePath);
     if (!content) continue;
 
+    // Fresh slugger per file so duplicate headers across files don't
+    // pollute each other.
+    const slugger = new Slugger();
+
     // Dice scan
     let match: RegExpExecArray | null;
     tagRegex.lastIndex = 0;