I should have clarified that it causes an access violation if you broadcast to a channel starting with the { char.

Hello,

If you replace the "{" with "\{" doesn't works? If doesn't works, just send me a sample code and I will test here.

Kind Regards,
Sergio

On the server:
Connection.DoSubscribe('{A467C487-AC66-41C8-8EBE-F8026F741EC7}');

And in OnMessage:
Server.Broadcast('hello', '{A467C487-AC66-41C8-8EBE-F8026F741EC7}');

An AccessViolation is generated OnLoadBalancerError: Access violation at address 006BE20E in module 'LoadBalancer.exe'. Read of address 00000000

On the server:
Connection.DoSubscribe('{A467C487-AC66-41C8-8EBE-F8026F741EC7}');

And in OnMessage:
Server.Broadcast('hello', '{A467C487-AC66-41C8-8EBE-F8026F741EC7}');

An AccessViolation is generated OnLoadBalancerError: Access violation at address 006BE20E in module 'LoadBalancer.exe'. Read of address 00000000

Hello,

The methods DoSubscribe and Broadcast doesn't make use of the internal JSON component, except, if the LoadBalancer is enabled (LoadBalancer.Enabled = true). If the LoadBalancer is enabled, then the message is converted to a JSON string, so the use of "{" or "}" should be escaped.
Are you really using a Load Balancer? if yes, how it's configured? attach a sample if possible because I've tested and I don't see this error.

Kind Regards,
Sergio