How to work around hung rman process when duplicating from active database

Applicable for Oracle 12.1.

During a "clone from active database" operation, I had a seemingly stuck restore process. It used a lot of time on restoring the controlfiles.

My clonescript was simple enough:

connect target /@mysrcdb
connect auxiliary /@myauxdb
run{
allocate channel c1 type disk;
allocate channel c2 type disk;
allocate auxiliary channel aux1 type disk;
allocate auxiliary channel aux2 type disk;
configure device type disk parallelism 2;
debug io;
DUPLICATE TARGET DATABASE TO myauxdb
FROM ACTIVE DATABASE
;
debug off;
}
exit

I noticed that the logfile wouldn't move beoynd this point:

DBGANY:     No untilscn in effect [17:44:29.012] (krmkicat)
RMAN-08016: channel aux1: starting datafile backup set restore
RMAN-08169: channel aux1: using network backup set from service mysrcdb
RMAN-08021: channel aux1: restoring control file

Solution:
On the axiliary server, set the parameter

DISABLE_OOB=on

in your $TNS_ADMIN/sqlnet.ora, and reexecute the duplicate-command again.

This is caused by a bug mentioned in Doc ID 2073604.1: "RMAN active duplicate hanging on restore control file" found on support.oracle.com