NSURLSessionDataTask completionHandler no longer executes when I switch to Release build configuration - objective-c

Question

I built a simple command line tool that fetches some data using an NSURLSessionDataTask. Now that I'm done coding, I find that the executable hangs when I switch to the Release build configuration in Xcode. I'm using a while loop that waits for the NSURLSessionData completionHandler to complete. The while loop works with Debug, but not with Release. If instead I use [NSThread sleepForTimeInterval:2.0f] to pause the code to wait for the completionHandler to complete, everything works fine in both Release and Debug, however I'd prefer to use the while loop as it is quicker and more logical.
Here is the relevant code:
// Configure Session
NSURLSessionConfiguration *config = [NSURLSessionConfiguration ephemeralSessionConfiguration];
// Authentication for the session
NSString *auth = [[[NSString stringWithFormat:#"%#:%#",cpanelUser, WxWaPpIUPA] dataUsingEncoding:NSUTF8StringEncoding] base64EncodedStringWithOptions:0];
config.HTTPAdditionalHeaders = #{#"Authorization":[NSString stringWithFormat:#"Basic %#",auth]};
NSURLSession *session = [NSURLSession sessionWithConfiguration:config];
// Run Data Task
__block BOOL taskComplete = NO;
NSURLSessionDataTask *task = [session dataTaskWithURL:urlComponents.URL
completionHandler:
^(NSData *data, NSURLResponse *response, NSError *error) {
if(error) {
// *HTTP response failed
NSInteger statusCode = [(NSHTTPURLResponse *)response statusCode];
[result addEntriesFromDictionary:queryReturn(EMAIL_TYPE_ERROR, [NSString stringWithFormat:#"There was a connection issue with the session data task.<br><br>Error: %# HTTP Status Code for the <a href='%#'>URL</a> requested: %li.",error,urlComponents.URL,statusCode])];
} else {
NSError *jsonError;
NSDictionary *jsonObject = (NSDictionary *)[NSJSONSerialization JSONObjectWithData:data
options:NSJSONReadingAllowFragments
error: &jsonError];
if(!jsonObject){
// *JSON parsing Error
[result addEntriesFromDictionary:queryReturn(EMAIL_TYPE_ERROR, [NSString stringWithFormat:#"There was an error while parsing the JSON data returned from cPanel.<br><br>Error: %#",jsonError])];
} else {
if([jsonObject[#"cpanelresult"] objectForKey:#"error"] != nil) {
// *cPanel API returned an Error
NSString *cpanelError = [NSString stringWithFormat:#"%#",[jsonObject[#"cpanelresult"] objectForKey:#"error"]];
if(verbose) NSLog(#"cPanel API 2 Error: %#\n", cpanelError);
[result addEntriesFromDictionary:queryReturn(EMAIL_TYPE_ERROR, [NSString stringWithFormat:#"cPanel API 2 returned an error while executing function '%#'.<br><br>Error: %#",funct, cpanelError])];
} else {
[result addEntriesFromDictionary:jsonObject];
}
}
}
taskComplete = YES;
}];
[task resume];
// Wait for task to complete
while(!taskComplete);
//[NSThread sleepForTimeInterval:2.0f];