High CPU usage of QUdpSocket after received ICMP TTL message

I have QUdpSocket object bound to a port, and I use it both for sending and receiving datagrams. But when my app receive ICMP 'TLL Exceeded' message, the communiction stops. Since then no packet is received, even if I see network traffic. The CPU usage raises, but the application remains responsive - user can click buttons and perform other actions.

The ICMP TTL Exceeded message for UDP sockets is hard to repoduce - I manged to get it only for OpenVPN connections, when firewall is turned off.

To reproduce this bug:
1. Download and install OpenVPN from https://openvpn.net/index.php/download/community-downloads.html
2. Copy 4 attached files: vpn_test.ovpn, vpn_test.key, vpn_test.pem, vpn_test.cert to your OpenVPN config subdirectory.
3. Start OpenVPN and click Connect (only one connection for this certifate is allowed).
4. Turn off firewall - this is very important !!!
5. Build & run 'qudpsocket_ttl_exceeded_bug' app.
6. Open taskmgr and check current cpu usage.
7. Set high value of TTL eg. 100 and click Test - CPU usage should be low.
8. Now set low value of TTL eg. 3 to generate ICMP 'TTL Exceeded' message, and click Test - CPU usage will raise, and will be high until app is closed.