Logstash falls from time to time. tcp input module error

Hello.

Sometimes our Logstash falls with such error in logs:

{:timestamp=>"2015-11-11T15:55:33.706000+0000", :message=>"An error occurred. Closing 
connection", :client=>"10.100.54.60:31166", :exception=>#<LogStash::ShutdownSignal: 
LogStash::ShutdownSignal>, :backtrace=>["org/jruby/ext/thread/SizedQueue.java:133:in `push'", 
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-tcp-1.0.0/lib/logstash/inputs/tcp.rb:122:in 
`handle_socket'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-codec-json_lines-
1.0.1/lib/logstash/codecs/json_lines.rb:38:in `decode'", 
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-codec-line-1.0.0/lib/logstash/codecs/line.rb:36:in 
`decode'", "org/jruby/RubyArray.java:1613:in `each'", 
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-codec-line-1.0.0/lib/logstash/codecs/line.rb:35:in 
`decode'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-codec-json_lines-
1.0.1/lib/logstash/codecs/json_lines.rb:37:in `decode'", 
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-tcp-1.0.0/lib/logstash/inputs/tcp.rb:118:in 
`handle_socket'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-tcp-
1.0.0/lib/logstash/inputs/tcp.rb:147:in `client_thread'", 
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-tcp-1.0.0/lib/logstash/inputs/tcp.rb:145:in 
`client_thread'"], :level=>:error}

On elastic Github I saw such error https://github.com/logstash-plugins/logstash-input-tcp/issues/12 but I am not sure if this a root cause of problem or it is just Logstash cant close its process correct.

Could somebody help me?

PS. I use Logstash 1.5.5 and Amazon Linux (AWS).

PPS. Seems that this problem also occurred in other people LS forwarder erroring out on the LS server