I just noticed that when you click OK on the popup, the client sends an opcode:
Code:
[Debug] [CLIENT__NET_ERR] Dsfvxcbcx: Unhandled incoming opcode: [OpCode OP_Unknown (0x3816) Size=8]
0: 00 00 00 00 FF FF FF FF | ........
The second 4 bytes are the contents of unknown4232 from the struct.