We found that beginRequest(with:) stops returning any result in a mid of the process with iOS13.2 Beta2 in the following cases.
1. Turn on CallDirectory in "Settings"→"Phone"→"Call Blocking & Identification"
→It stops when the number of registered phone numbers exceeds a thousand.
2. Update its data by calling CXCallDirectoryManager.sharedInstance.reloadExtension in an app.
→It stops when the number of registered phone numbers exceeds 3024.
This bug doesn't happen in iOS13.1.2 or before.
We confirm the registration with a log like "Added XXXX phone number identification entries" and it shows the extension completes an update with 3000 data which is relatively a small number. If we, however, restart the reload extension it stops in the mid of the process.