[Bug]: Rivet editor shows wrong data flow

### What happened?

In a case where:
- Executor is "Node"
- An array is fed into a subgraph
- The subgraph is in "Split - Sequential" mode
- The subgraph has a code node with compute-intensive code

the editor shows wrong dataflow in a subgraph when switching between runs (1, 2).

You can see wrong data flow after the "MATCH" node:


### What was the expected functionality?

The editor shows correct dataflow in a subgraph when switching between runs (1, 2).

### Describe your environment

Windows, Rivet 1.10.1

### Relevant log output

```shell

```

### Relevant screenshots

_No response_

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Start by reproducing the issue in the Rivet editor with the Node executor, an array-fed subgraph in Split - Sequential mode, and a compute-intensive code node. Switch between runs 1 and 2 and inspect the dataflow after the MATCH node; done means the subgraph displays the correct dataflow for both runs.

Written by the indexing model from the issue text.