RefetchQueriesFunction does not receive mutation result as first parameter and is not documented

Intended outcome:

Inside reftechQueries, I need the response of the original mutation to use the result as a variable for the refetch query.
I saw, even if not really documented, that a RefetchQueriesFunction is accepted as refetchQueries.
Trying to retro-engineer how this function would work, I print the arguments received to the console an see that the response is sent as first argument!
Typescript tells me that the function should return a Array<string | PureQueryOptions>.
Great, this is exactly what I need.

Actual outcome:

The actual outcome is, at runtime the first argument that as the exact same shape as data in

const { data } = useQuery(...)
//      ^

is undefined. (the prop inside data is actually undefined).
So for a mutation called addPost, data.addPost will be undefined at runtime.
The fact that the console shows the data on console.log is probably due to a pointer value being updated and the console shows the updated value.

So, I see two options here:
1/ My retro-engineering is wrong and the RefetchQueriesFunction should be documented.
2/ My retro-engineering is right and something is wrong in the implementation of RefetchQueriesFunction. Maybe response is not awaited properly or something ?

How to reproduce the issue:

I guess this is pretty straightforward, if you need any additional info just tell me :)

Versions

System:
    OS: Linux 4.19 Alpine Linux
Binaries:
    Node: 12.16.3 - /usr/bin/node
    Yarn: 1.22.4 - /usr/local/bin/yarn
    npm: 6.14.5 - /usr/bin/npm
npmPackages:
    @apollo/client: ^3.2.0 => 3.2.0
    apollo-upload-client: ^14.1.1 => 14.1.1

I'm open to creating a PR if needed.
Thanks for your wonderful work 👏

Start by tracing the refetchQueries option and RefetchQueriesFunction behavior described in the issue, then reproduce the addPost mutation case with Apollo Client 3.2.0. The issue names no source file or test; done means establishing whether the mutation result is available as the first argument and either correcting that behavior or documenting the supported contract.