Could use a test scenario or code to reproduce the issue, so we can see if it is fixed.

Sorry, i don't know how correct reproduce issue or write clear test.
But i can show, how i do it.
Use checkManagerAPI() in AsterNET.Test.
Set manager.PingInterval = 1;. It is need for increase chance catch bug.
Somewhere in 'while loop' in ManagerReader.Run() set Console.WriteLine("Thread = " + Thread.CurrentThread.ManagedThreadId);
It is help you see, that we still read from socket.
And finally, on Asterisk execute :
for i in {1..10}; do /usr/sbin/asterisk -rx'core restart now'; date; sleep 5; done.
You will see, that usually after 1-3 restart asterisk, we stop listen ami.

I haven't had the time to test this right now. Not sure when I will have the time.

But feel free to add some code snippets to make testing easier.