Steps to reproduce:

1. Create a new item of type 'script' with type of information 'log', and add a matching log time format (yyyy-MM-ddThh:mm:ssZ). Insert script that outputs log data in the form: "<timestamp> <data>\n"
2. Navigate to Monitoring->Latest Data.  Select host and then new script item 'history'.

Result:
See screenshot.  All lines are grouped together with a single (zabbix) timestamp.

Expected:
Each line of log data would parsed individually with matching timestamp.