We're creating the symbol library, so if it's not in the cache, then it's not in the library.

eeschema/sch_io/altium/sch_io_altium.cpp

@@ -3653,10 +3653,6 @@ void SCH_IO_ALTIUM::ParsePowerPort( const std::map<wxString, wxString>& aPropert
     {
         libSymbol = powerSymbolIt->second; // cache hit
     }
-    else if( LIB_SYMBOL* alreadyLoaded = m_pi->LoadSymbol( getLibFileName().GetFullPath(), symName ) )
-    {
-        libSymbol = alreadyLoaded;
-    }
     else
     {
         libSymbol = new LIB_SYMBOL( wxEmptyString );