Repro steps:
1) Open the Sockets.zip project and Main.scene in it
2) Create a hotspot for a device from which you could condition your network
3) Build and run the scene on a iOS 8/9 device
4) In XCode, open up the Network Link Conditioner from additional developer tools
5) In the device click Connect 5222 button and Disconnect 5222 button after few seconds
6) Turn on Network Link Conditioner with 100% Loss profile
7) Click Connect 433 on the device
8) Notice the crash after a few seconds

Reproduced in: 5.4.0b18; 5.3.5p1; 5.2.4f1
iPhone5s 9.2.1; iPad2 8.1.2