I can reproduce an issue with master; v0.17.1rc1 works fine.

Steps to reproduce:
- `bitcoin-qt -regtest`
- open Console window
- repeat `generatetoaddress 1 AN_ADDRESS` some times until crash

Crash occurs both on wayland and x11.

[debug.log](https://github.com/bitcoin/bitcoin/files/2690776/debug.log)

[wallets.zip](https://github.com/bitcoin/bitcoin/files/2690781/wallets.zip)
{
#ifndef Q_OS_MAC
    
    if (!trayIcon)
        return;
    trayIconMenu = new QMenu(this);
    trayIcon->setContextMenu(trayIconMenu);
    connect(trayIcon, &QSystemTrayIcon::activated, this, &BitcoinGUI::trayIconActivated);
#else
    
    MacDockIconHandler *dockIconHandler = MacDockIconHandler::instance();
    connect(dockIconHandler, &MacDockIconHandler::dockIconClicked, this, &BitcoinGUI::macosDockIconActivated);
    trayIconMenu = new QMenu(this);
    trayIconMenu->setAsDockMenu();
#endif
    
#ifndef Q_OS_MAC
    
    trayIconMenu->addAction(toggleHideAction);
    trayIconMenu->addSeparator();
#endif
    if (enableWallet) {
        trayIconMenu->addAction(sendCoinsMenuAction);
        trayIconMenu->addAction(receiveCoinsMenuAction);
        trayIconMenu->addSeparator();
        trayIconMenu->addAction(signMessageAction);
        trayIconMenu->addAction(verifyMessageAction);