That is very strange. If those application fields are set to save to a custom field that is of the type radio, then the application field itself should be marked as
text. I’ve tried creating a couple applications and custom fields on my test site that mirror yours and they are always created correctly (the type of the application field is always
radio which in turn allows a json object to be set as the value).
Do you have any knowledge of how those custom fields were created, or how the applications fields were linked to them? Without being able to get my data into the same state as yours, it’s hard to diagnose the original issue that would have caused those fields to get into that mismatched state. All the normal methods of creating application fields on my site result in what I’d expect.
Could you perhaps try recreating those application fields in the UI and re-linking them to the custom fields, and then seeing if the new application fields of are of the correct type? Once those application fields become the correct type, then your original json should start working (you’ll just need to change the old application fields ids to the newly created ones). If you are unable to get those fields create as
radio fields, then I’ll have to dig into why your site in particular is having that issue and not mine.