Details about DATETIME type in the Field Converter:

I noticed that the output while previewing a DateTime conversion seems to change the actual date. E.g. from string "07/19/2016" to DateTime Jul 18, 2016 4:00:00 PM 

While this seems like a bug, it's not. SDC uses the browser's timezone to display dates in the UI. Moodify Streamsets Data Collector to use a specific time zone. Go to HELP in the top right corner and click on Settings.

After modifying this setting you'll see 

References

https://groups.google.com/a/streamsets.com/forum/#!topic/sdc-user/S3bfsrMOYJk

https://groups.google.com/a/streamsets.com/forum/#!topic/sdc-user/xsAvMdf0EIM

https://streamsets.com/documentation/datacollector/latest/help/