"Batch Cache Operations" contains a parable that confuses me

https://w3c.github.io/ServiceWorker/#batch-cache-operations specifies the following step 4.2.3 under "Output":

If the result of running Query Cache with operation’s request, operation’s options, and addedItems is not empty, throw an "InvalidStateError" DOMException.

I don't understand how would this be correct for a "put" operation? To explain my confusion, I'd expect querying of the cache for which put method has been called, to maybe contain a cache hit for a matching request, meaning the "query cache" procedure may return a non-empty list (if equivalent request was there). Why should the implementation throw an InvalidStateError then? Or am I reading the entire parable in wrong context? The later step 4.2.6.6 instructs to run the "query cache" procedure again:

Set requestResponses to the result of running Query Cache with operation’s request.

Doesn't the above read more or less exactly like 4.2.3, while the latter already expects any result (an empty or non-empty list) while the former would have thrown had the cache querying returned a non-empty list?

I must be reading the spec. wrong, but I just can't seem to squint my eyes the right way to see if I can make sense of the above for my part.

Read the Service Worker specification's “Batch Cache Operations” algorithm, especially step 4.2.3 under “Output” and step 4.2.6.6, alongside the linked “Query Cache” procedure. Determine whether the two steps are inconsistent or whether the surrounding conditions clarify their different roles; done means documenting the resolution or proposing precise spec wording.