It looks like Go's RFC3389 time parser is failing on that timestamp. This recreates the issue. The full error is:
parsing time "2017-06-02T21:40:59+0000" as "2006-01-02T15:04:05Z07:00": cannot parse "+0000" as "Z07:00"
Maybe the time parser should be a bit more robust and try a few more common formats.
For now you will need to use Logstash to handle this.