Ssynchronous mode for reloads via Qlik Web Connectors (Asynchronous requests) only works as expected for data resources (like for example JSON files) that have a static schema.
You might not get the expected results if you reload from data resources with a dynamic structure like for example:
In this case if you reload those 2 JSON files via General QWC with asynchronous mode, most likely the "middleName" won't be reloaded in Qlik Sense because it is using the first file (File1) to generate the table structure and then with subsequent tables it is pulling the same columns where they are found.
A feature request has been created in the community in order to improve this functionality:
The information in this article is provided as-is and to be used at own discretion. Depending on tool(s) used, customization(s), and/or other factors ongoing support on the solution below may not be provided by Qlik Support.