AEP Data Prep - Support path to nested data structure

Currently, it seems that even though the data prep UI suggests this is possible, that mapping a nested data structure to a target field as a calculated field is not supported and ends up in a stalled data ingestion.

Example: I have a nested source data structure, from which I want to extract a specific email address from index 0 of an array. This will always be the same index.

Now, when I try to use data prep functions, the green checkmark appears, as well as the desired email address in the preview.

So far, everything looks as it should work. Until you start the workflow and it never ends.

Now, I was 99% done creating my support ticket, when I read the AI-suggested ticket solution

Possible solutions

1. best case: Adobe integrates support for this deterministic path. 
2. acceptable case: fix the UI to not show the false positive and maybe instead point out the issue.
3. worst case: nothing changes, and I won’t be the last to scratch his head about this

This surely has potential performance implications for even more complex data structures, but either way, I think 1. is the way to go for an enterprise grade solution like the RT-CDP since Adobe cannot expect everyone to have full flexibility about the delivered data structure or have intermediate tools to modify the incoming data as needed.