diff --git a/services/web/frontend/js/features/source-editor/lezer-typst/tokens.mjs b/services/web/frontend/js/features/source-editor/lezer-typst/tokens.mjs
index 557614d5ec..186b9945c4 100644
--- a/services/web/frontend/js/features/source-editor/lezer-typst/tokens.mjs
+++ b/services/web/frontend/js/features/source-editor/lezer-typst/tokens.mjs
@@ -105,6 +105,20 @@ export const rawTokenizer = new ExternalTokenizer(
     }
 
     if (stack.canShift(RawBlockBody)) {
+      // Guard: must genuinely follow a RawBlockOpen (which ends with \n).
+      // Walk backward past any lang tag (A-Za-z0-9) and require ```.
+      // This blocks spurious LALR-merged states from consuming body text.
+      if (input.peek(-1) !== NEWLINE) return
+      let back = -2
+      while (
+        (input.peek(back) >= 65 && input.peek(back) <= 90) ||
+        (input.peek(back) >= 97 && input.peek(back) <= 122) ||
+        (input.peek(back) >= 48 && input.peek(back) <= 57)
+      ) { back-- }
+      if (input.peek(back)     !== BACKTICK ||
+          input.peek(back - 1) !== BACKTICK ||
+          input.peek(back - 2) !== BACKTICK) return
+
       let hasContent = false
       while (input.next !== -1) {
         if (