iOS CrashReport never getting populated after crahes

So I'm trying to implement the new CrashReport API running Unity Pro and iOS Pro (4.2.0f4) and deploying to a device (ipad mini), but the CrashReport.latestReport and CrashReport.reports objects are never populated even after I force an unhandled exception. My CrashReporter.h looks as follows:

 // Enabling this will force app to do a hard crash instead of a nice exit when UnhandledException
 // is thrown. This will force iOS to generate a standard crash report, that can be submitted to
 // iTunes by app users and inspected by developers.
 #define ENABLE_IOS_CRASH_REPORTING 1
 
 // Enable custom crash reporter to capture crashes.
 #define ENABLE_CUSTOM_CRASH_REPORTER 1
 
 // Enable submission of custom crash reports to Unity servers. This will enable custom crash
 // reporter.
 #define ENABLE_CRASH_REPORT_SUBMISSION 1
 
 
 #if ENABLE_CRASH_REPORT_SUBMISSION && !ENABLE_CUSTOM_CRASH_REPORTER
     #undef ENABLE_CUSTOM_CRASH_REPORTER
     #define ENABLE_CUSTOM_CRASH_REPORTER 1
 #endif
 
 void WaitWhileCrashReportsAreSent();
 void SubmitCrashReportsAsync();
 void InitCrashReporter();

and my method to report the crashes looks like this (SendDirectFeedback is a method that sends a feedback email to our dev team via TestFlight):

 public static string SendMostRecentCrashReport()
     {
         Debug.Log("Sending most recent crash report if it exists");
 #if UNITY_IPHONE
         var report = CrashReport.lastReport;
         if (report != null || (CrashReport.reports != null && CrashReport.reports.Length > 0))
         {
             Debug.Log("crash report exists. Report count: " + CrashReport.reports.Length);
             if (report == null)
                 report = CrashReport.reports[0];
             string crashReport = "App encountered crash, but was able to gather the following crash report on restart: " +
                 "\nTime: " + report.time.ToString("G") + 
                 "\nReport: " + report.text;
 
             SendDirectFeedback(crashReport);
             return crashReport;
         }
 #endif
         return null;
     }

but I return null every time (and obviously never get the email via TestFlight). Has anyone else had any luck with this new feature? Did I miss some other setup step or does it only handle certain types of exceptions? I've tried running as a development build and not as a development build, but I get the same behavior either way. Thanks for any help. Also, I tried to tag this question as "CrashReport" but since I don't have 50 rep it won't let me create a new tag.