I get a string with custom field Date Time Range picker generated from plugin *scriptrunner* like thist "Thu Jul 14 10:32:07 AEST 2016"

I get a string with custom field Date Time Range picker generated from scriptrunner like thist "Thu Jul 14 10:32:07 AEST 2016"

When I map it as ${dateformat("yyyy-MM-dd"):JQLIssues[i].MyField} I get an empty string but should give the date like 2016-10-06