CDS/CDNSKEY are not published with BIND-9.16.1 and dnssec-policies

[Tom]

Hi
Using BIND-9.16.1.
In the last ISC dnssec webinar 
(https://www.youtube.com/watch?v=2aB__FZZQ84) I heared, that CDS/CDNSKEY 
records automatically should be published when using dnssec-policies.

My policy looks like this:
dnssec-policy "test-policy" {
	dnskey-ttl 60;
	keys {
		ksk lifetime unlimited algorithm ecdsa256;
		zsk lifetime unlimited algorithm ecdsa256;
	};
};

and the zone like this:
zone "example.com" {
         type master;
         file "master/example.com.zone";
         key-directory "/etc/named/keys/example.com";
	dnssec-policy "test-policy";
};


When digging this zone for CDS/CDNSKEY records, then these keys are not 
existing:
$ dig +norec +noall +answer @127.0.0.1 cds example.com
$ dig +norec +noall +answer @127.0.0.1 cdnskey example.com

The keyfile for "example.com" also do not show a "published"-date:
$ cat Kexample.com.+013+02624.key
; This is a key-signing key, keyid 2624, for example.com.
; Created: 20200409061638 (Thu Apr  9 08:16:38 2020)
; Publish: 20200409061638 (Thu Apr  9 08:16:38 2020)
; Activate: 20200409061638 (Thu Apr  9 08:16:38 2020)
example.com. 60 IN DNSKEY 257 3 13 
uV/NtPZSL1fmO3FAi4pZCcbTl19iD3SizgVcDXGJEl1g4l/cHUGvVl33 
3cx2cODA6RUj55pZa77g1VBtFBXByg==


Any hints, why in this case the dnssec-policy mechanism doesn't publish 
the CDS/CDNSKEY records?

Many thanks.

Kind regards,
Tom