Are FHIR-resource-Logical-Id's MANDATORY for "contained" fhir-resources? - hl7-fhir

Question

I'm trying to get a clarification
Under the definition of what is a (fhir-resource-logical-id)
https://www.hl7.org/fhir/resource-definitions.html#Resource.id
The comment says:
The only time that a resource does not have an id is when it is being submitted to the server using a create operation.
We have having an internal "debate" on the "contained-reference".
https://build.fhir.org/references.html#contained
Example one from the article:
JSON
{
"resourceType" : "Condition",
"contained": [
{
"resourceType" : "Practitioner",
"id" : "p1",
"name" : [{
"family" : "Person",
"given" : ["Patricia"]
}]
}],
"asserter" : {
"reference" : "#p1"
}
}
XML
<Condition xmlns="http://hl7.org/fhir">
<contained>
<Practitioner>
<id value="p1"/>
<name>
<family value="Person"/>
<given value="Patricia"/>
</name>
</Practitioner>
</contained>
<!-- other attributes -->
<asserter>
<reference value="#p1" />
</asserter>
<!-- other attributes -->
</Condition>
So the "p1" (as the fhir-resource-logical-id) is populated....under the contained resourceType of "Practitioner".
So far, so good.
But there is another example with a comment in the example: (below xml)
<Patient xmlns="http://hl7.org/fhir">
<id value="something"/>
<contained>
<Provenance>
<!-- no id necessary (though still allowed) -->
<target>
<reference value="#"/>
</target>
</Provenance>
</contained>
<!-- other attributes -->
</Patient>
The xml-comment-part is (and I'll refer to this as the "comment-documentation") is:
<!-- no id necessary (though still allowed) -->
We are confused. Is this a "Provenance-ONLY" comment for a contained FHIR resource?
Or does this comment-documentation "
<!-- no id necessary (though still allowed) -->
" .. does this "comment-documentation" apply to any/all "contained" Fhir-Resource(s)?
The "comment-documentation" seems in conflict with the "The only time that a resource does not have an id is when it is being submitted to the server using a create operation" rule.
Another way to put it:
Does the rule "The only time that a resource does not have an id is when it is being submitted to the server using a create operation" (always and always) apply to "contained"-fhir-resources?
Thank you.

Answer 1

I wrote that, and I think I was just wrong when I did - just thinking that it wasn't needed functionally in that context, and didn't check whether it had to be present. This is a case where id is required