fix: don't access protected member from within lambda function (CURA-2704)
fix: don't access protected member from within lambda function (CURA-2704)

alephobjects/CuraEngine,Ultimaker/CuraEngine,alephobjects/CuraEngine,Ultimaker/CuraEngine,alephobjects/CuraEngine,ROBO3D/CuraEngine,ROBO3D/CuraEngine,ROBO3D/CuraEngine