Multiline filter creates array of messages instead single event with single line

Description

Hi
First of all i must thank you guys for having this awesome tool, logstash is really great.
Unfortunately i'm having some issues with structuralizing logs which contains java exceptions, while regular (single line) events are parsed without any hiccups, using the multiline parser is a all different case.

as i want to upload the data into bigquery i must have a single event which is a single line, and using the multiline filter i've managed to reach a case when i have a single event with an array of lines (messages)

is there any (simple or not so simple) way to configure multiline parser to do so?

here is my config file content:

and here are the results i'm having:

Environment

None

Status

Assignee

Logstash Developers

Reporter

Dave Ezrakhovich

Labels

None

Affects versions

Priority

Configure