Can't find an optimistic response within `commitLocalUpdate` updater's store

Let's say you have this in your graphql schema:
```graphql
type Comment {
id: ID!
content: String!
}
```

and this in your client extension:
```graphql
extend type Comment {
selected: Boolean
}
```
When creating a comment with a mutation, you can easily create an optimistic response for the newly created `Comment`.

Let's say I want to change the `selected` field on click, I'd use `commitLocalUpdate` to do so.

```js
commitLocalUpdate(environment, store => {
const { updatableData } = store.readUpdatableFragment(fragment, comment);
updatableData.selected = true
});
```
This works for the comments from the server, but this breaks when doing so on the comment from an optimistic response:
```
Uncaught Invariant Violation: No record with client:local:0 was found. This likely indicates a problem with Relay.
```
```
Warning: A store update was detected within another store update. Please make sure new store updates aren't being executed within an updater function for a different update.
```

Could be that `commitLocalUpdate` updater's store gets its recordSource from `_recourdSource` instead of the `_optimisticSource` that is supposed to contain the optimistic responses too.

edit: experienced with relay 18.2.0.