Application crash in QML after updating QT from 5.6 to 5.7

Application uses QML. After updating QT to 5.7 application start crashing, if you close application.
Call stack -
I found crash. If you use

QQmlContext* tableContext = m_table->rootContext();
tableContext->setContextProperty("MyWidget", this);

Before closing part that depend on QML-Model-View, you have to do it:

QQmlContext* tableContext = m_table->rootContext();
tableContext->setContextProperty("MyWidget", nullptr);

It like reset pointer to nullptr for QML.
QT 5.6 does not have this problem.