Subgraph double nested execution does not trigger

- [ ] Debug and identify source of issue: start with ensuring prompt contains all nodes and proper execution ID -> determine if backend or frontend error
- [ ] Make plan to solve issue

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-4632-Subgraph-double-nested-execution-does-not-trigger-2416d73d365081e78f54d4d2aee29132) by [Unito](https://www.unito.io)

Start by checking whether the prompt contains all nodes and whether the execution ID is correct, as specified in the issue. Trace the double-nested subgraph execution far enough to determine whether the problem is in the backend or frontend, then document the source and make a plan to resolve it.

Written by the indexing model from the issue text.