Support SDK - Guide search call failing (403 response), Android and iOS

Hi there, 

I was referred here by a Zendesk support agent, hoping this community and Developer Support can help. 

We are currently experiencing an issue with our Support SDK implementation for Android and iOS. The Guide search function is failing, we get a 403 error with the below message for the api/mobile/ calls: 

{"error":"Forbidden","description":"You are missing the following required scopes: "}

All other functions (Guide articles, form, submit ticket) work without any issues and our code has not been touched in several years. 

1. We see that the Zendesk demo app uses the zendesk.android library and we use the zendesk.core library
2. The call is being made with authentication to a public endpoint and works on a browser with no authentication but this is how we've always made the calls and they are generated automatically inside the SDK library. 
3. What has been changed in the “zendesk.core” library recently so that we can’t receive responses (403) with the authentication?
4. If there was a change - should we have received an update?
5. What actions can we do to fix this? 

Thanks!