nested content AngularJS template issue after 13.3 upgrade

[shearer3000]

Which Umbraco version are you using? (Please write the exact version, example: 10.1.0)

13.3.0

Bug summary

We have a CMS upgraded to Umbraco 13, so it has preexisting content based on the nested content editor (appreciate this is now marked as legacy, and to be removed in Umbraco 14).

After upgrading to 13.3.0, we've noticed that when editing content, the AngularJS template property of the nested content definition no longer works i.e. a template of "{{section[0].name}}" no longer displays what the syntax prescribes, but just "Item x" instead e.g. "Item 1".

This wasn't an issue in 13.1, 13.2.

Specifics

No response

Steps to reproduce

Edit content that uses a nested content property editor by modifying any existing content or adding new content, observe whether the AngularJS template syntax reflects the underlying content

In the following screenshot, the green box represents existing content (added in prior Umbraco 13 minor version), item 1 was existing content that was changed, and item 6 was newly added (after the Umbraco 13.3 upgrade)

Edit: in this case, the syntax is to target content authored with a Umbraco.MultiUrlPicker editor

Expected result / actual result

Expected: the syntax defined by the AngularJS template works Actual: syntax not working and editor show default index value instead eg. "Item 1", "Item 6"