It's not an issue, it works as expected, but that's because of an option you most likely mistakenly used:
You've ordered a power down (withdraw_vesting_operation) but it is processed using settings that you've set for it via set_withdraw_vesting_route, in a way, that 100% of power down goes to yourself with automatic power up:

"from_account":"purepinay"
"to_account":"purepinay",
"auto_vest":true,

In order to get liquid HIVE, you would have to stop power down, set it to yourself WITHOUT 100% auto vest (i.e. without 100% power up) and start power down again.