SOA Minimum comment in "dig" output

[Carsten Strotmann]

Hi,
 
here is a question I've got during a DNS training, and I still do not
have a good answer:
 
----

RFC 2308 "DNS NCACHE" defines the last field of the SOA RR as "the TTL of
negative responses".
 
; <<   DiG 9.10.3-P4-Ubuntu <<   +noall +answer +multi +cmd soa
example.com ;; global options: +cmd
example.com.         86326 IN SOA dns1.example.com.
hostmaster.example.com. ( 2018013002 ; serial
                                 900        ; refresh (15 minutes)
                                 300        ; retry (5 minutes)
                                 604800     ; expire (1 week)
                                 900        ; minimum (15 minutes)
                                  )
   
Why is dig still showing the old description "minimum" about the meaning
of the field?
 
----
 
Is there a good answer? This behaviour of "dig" is irritating users.
 
Best regards
 
Carsten