Exporting the keys in the mount mode

Hi,

In a particular workflow, I am attempting to the export the keys out of the keystore, when the database is in the mount mode.
I am able to successfully export the keys. It works fine for the versions Oracle 12.2, Oracle 18c, Oracle 19c.

I would like to know if it valid to export the keys when the database is in the mount mode.
Are there any OPEN bugs ?

thanks in advance,
Mahantesh

I have posted the steps below. 

STEP 1: OPEN the database in the mount mode:

[oracle@gi-rhel77 ~]$ $ORACLE_HOME/bin/sqlplus / as sysdba

SQL*Plus: Release 18.0.0.0.0 - Production on Thu Dec 19 18:50:11 2019