Question about additional section in BIND-responses

[Tom]

On 8/17/22 02:27, Evan Hunt wrote:
> On Tue, Aug 16, 2022 at 05:28:19PM +0200, Tom wrote:
>> Using BIND-9.18.5 as a recursive server:
>> What's the reason, that BIND answers with the additional section for the
>> the following query where for example Knot resolver and also PowerDNS
>> resolver doesn't add the additional section for the same query?
>>
>> [...]
>>
>> Any hints why BIND adds the additional section while other resolvers
>> doesn't? Is there an option in BIND to behave like Knot/PDNS?
> 
> The option is "minimal-responses".  If you set it to "yes", it will omit
> authority and additional section data except when necessary.
> 
> The default is "no-auth-recursive", which omits authority section data
> when it isn't strictly necessary, but will still add additional data for
> records in the answer section.
> 

I've already set "minimal-responses yes;", but the additional 
section/data is still shown. So based on your explanation, BIND assumes, 
this data is necessary, why? And why behaves BIND different here than 
Knot/PDNS where no additional section is shown for the same query?