diff -up doxygen-1.9.1/src/docparser.cpp.me doxygen-1.9.1/src/docparser.cpp

--- doxygen-1.9.1/src/docparser.cpp.me	2021-02-10 10:52:09.481086282 +0100

+++ doxygen-1.9.1/src/docparser.cpp	2021-02-10 10:55:32.418781686 +0100

@@ -951,7 +951,7 @@ static void handlePendingStyleCommands(D

       children.append(new DocStyleChange(parent,g_nodeStack.count(),sc->style(),sc->tagName(),FALSE));

       g_initialStyleStack.push(sc);

       g_styleStack.pop();

-      sc = g_styleStack.top();

+      sc = !g_styleStack.isEmpty() ? g_styleStack.top() : 0;

     }

   }

 }