diff --git a/sc/source/core/data/column4.cxx b/sc/source/core/data/column4.cxx
index ae3cd16fffa7..f6dac8ae3c65 100644
--- a/sc/source/core/data/column4.cxx
+++ b/sc/source/core/data/column4.cxx
@@ -1667,6 +1667,10 @@ static bool lcl_InterpretSpan(sc::formula_block::const_iterator& rSpanIter, SCRO
             // Found a completely dirty sub span [nSpanStart, nSpanEnd] inside the required span [nStartOffset, nEndOffset]
             bool bGroupInterpreted = pCellStart->Interpret(nSpanStart, nSpanEnd);
 
+            if (bGroupInterpreted)
+                for (SCROW nIdx = nSpanStart; nIdx <= nSpanEnd; ++nIdx, ++itSpanStart)
+                    assert(!(*itSpanStart)->NeedsInterpret());
+
             ScRecursionHelper& rRecursionHelper = rDoc.GetRecursionHelper();
             // child cell's Interpret could result in calling dependency calc
             // and that could detect a cycle involving mxGroup
@@ -1686,7 +1690,15 @@ static bool lcl_InterpretSpan(sc::formula_block::const_iterator& rSpanIter, SCRO
                 ++itSpanStart;
                 for (SCROW nIdx = nSpanStart+1; nIdx <= nSpanEnd; ++nIdx, ++itSpanStart)
                 {
-                    (*itSpanStart)->Interpret(); // We know for sure that this cell is dirty so directly call Interpret().
+                    if( !(*itSpanStart)->Interpret()) // We know for sure that this cell is dirty so directly call Interpret().
+                    {
+                        SAL_WARN("sc.core.formulagroup", "Internal error, cell " << (*itSpanStart)->aPos
+                            << " failed running Interpret(), not allowing threading");
+                        bAllowThreading = false;
+                        return bAnyDirty;
+                    }
+                    assert(!(*itSpanStart)->NeedsInterpret());
+
                     // Allow early exit like above.
                     if ((mxParentGroup && mxParentGroup->mbPartOfCycle) || !rRecursionHelper.AreGroupsIndependent())
                     {
@@ -1788,7 +1800,19 @@ static void lcl_EvalDirty(sc::CellStoreType& rCells, SCROW nRow1, SCROW nRow2, S
                     else
                     {
                         // No formula-group here.
-                        bool bDirtyFlag = (*itCell)->MaybeInterpret();
+                        bool bDirtyFlag = false;
+                        if( (*itCell)->NeedsInterpret())
+                        {
+                            bDirtyFlag = true;
+                            if(!(*itCell)->Interpret())
+                            {
+                                SAL_WARN("sc.core.formulagroup", "Internal error, cell " << (*itCell)->aPos
+                                    << " failed running Interpret(), not allowing threading");
+                                bAllowThreading = false;
+                                return;
+                            }
+                            assert(!(*itCell)->NeedsInterpret());
+                        }
                         bIsDirty = bIsDirty || bDirtyFlag;
 
                         // child cell's Interpret could result in calling dependency calc