Logstash stops processing and submitting events if a log-message contains certain character sequences

See the GIST for logmessage, debugoutput, logstash.conf and patterns - https://gist.github.com/magicdude4eva/5b71f02c8e36098a064e

I can reproduce this on 1.5.4 and 2.0 - as soon as Logstash starts processing those records it will hang and not process any further log-records. Logstash needs to be restarted and it will then continue.

I believe that in the logfile example (https://gist.github.com/magicdude4eva/5b71f02c8e36098a064e#file-logfileexample-txt) the issue is caused by line 2.