Critical error in multiline filter plugin

Description

My logstash instance works in production.
And while reading multiline messages, I had several time the following error in multiline filter plugin, which makes all logstash KO (it stops to process next log messages until I restart it).
I don't have the message that causes the problem.
the input is tcp.

Here the logstash log about this error :

Environment

None

Status

Assignee

Logstash Developers

Reporter

Fabien Baligand

Labels

None

Affects versions

Priority

Configure