diff --git a/sc/source/core/tool/formulaopt.cxx b/sc/source/core/tool/formulaopt.cxx
index 5b8ec5e9165d..a49899166c20 100644
--- a/sc/source/core/tool/formulaopt.cxx
+++ b/sc/source/core/tool/formulaopt.cxx
@@ -70,6 +70,9 @@ void ScFormulaOptions::SetDefaults()
     bUseEnglishFuncName = false;
     eFormulaGrammar     = ::formula::FormulaGrammar::GRAM_NATIVE;
 
+    // unspecified means use the current formula syntax.
+    eIndirectFuncRefSyntax = formula::FormulaGrammar::CONV_UNSPECIFIED;
+
     ResetFormulaSeparators();
 }