After stopsystem command, mysql's PID is not cleared in PID

Build tested: 1.4.3-4, Azure build 20200227

After executing the stopsystem command, getprocessstatus still showing mysqld is ACTIVE, along with it's PID, but process mysqld is no longer exist.

mcsadmin> getprocessstatus
getprocessstatus Fri Mar 6 16:41:58 2020

MariaDB ColumnStore Process statuses

Process Module Status Last Status Change Process ID
------------------ ------ --------------- ------------------------ ----------
ProcessMonitor pm1 ACTIVE Fri Mar 6 16:39:38 2020 3622
ProcessManager pm1 ACTIVE Fri Mar 6 16:39:45 2020 3719
DBRMControllerNode pm1 MAN_OFFLINE Fri Mar 6 16:41:40 2020
ServerMonitor pm1 MAN_OFFLINE Fri Mar 6 16:41:40 2020
DBRMWorkerNode pm1 MAN_OFFLINE Fri Mar 6 16:41:40 2020
PrimProc pm1 MAN_OFFLINE Fri Mar 6 16:41:40 2020
ExeMgr pm1 MAN_OFFLINE Fri Mar 6 16:41:40 2020
WriteEngineServer pm1 MAN_OFFLINE Fri Mar 6 16:41:40 2020
DDLProc pm1 MAN_OFFLINE Fri Mar 6 16:41:40 2020
DMLProc pm1 MAN_OFFLINE Fri Mar 6 16:41:40 2020
mysqld pm1 ACTIVE Fri Mar 6 16:41:46 2020 3860

debug.log showed that mysqld was kill by OAM:

Mar 6 16:41:42 localhost ProcessMonitor[3622]: 42.781458 |0|0|0| D 18 CAL0000: statusControl: REQUEST RECEIVED: Set Process pm1/mysqld State = MAN_OFFLINE
Mar 6 16:41:42 localhost ProcessMonitor[3622]: 42.781529 |0|0|0| D 18 CAL0000: Stop MySQL Process
Mar 6 16:41:42 localhost ProcessMonitor[3622]: 42.782389 |0|0|0| D 18 CAL0000: statusControl: Set Process pm1/mysqld State = MAN_OFFLINE PID = 0

This may have been a side effect of the implementation of MCOL-3718.