Legato Api not working

Hi,
le_ulpm_ShutDown()
Above mentioned api return LE_OK but the module not turning off .And sometimes the api works it let into module turn off condition .

Device: WP7608
Legato Version:18.06.3_72bae80dcf4e2d36453435468a5ceaa3_modified
Firmware Version: SWI9X07Y_02.16.02.00 000000 jenkins 2018/04/19 19:59:02
Bootloader Version: SWI9X07Y_02.16.02.00 000000 jenkins 2018/04/19 19:59:02
MCU Version: 002.009

Thanks in advance

how about using AT!POWERMODE command?
Also is this occuring in R13.3?