Missing buttons from AirPrint dialog

Hi

I've implemented AirPrinting from my app but I'm facing a strange issue. Whenever the print dialog appears, there are no Cancel or Done/Print buttons displayed, as shown in the following image.

https://www.dropbox.com/s/ahuam1qplryvqta/airprint_problem1217.jpg?dl=0

The code I'm using is as follows:

if ([UIPrintInteractionController canPrintURL:pdfUrl]) {
        UIPrintInfo *aPrintInfo = [UIPrintInfo printInfo];
        aPrintInfo.outputType = UIPrintInfoOutputGeneral;
        aPrintInfo.jobName = [NSString stringWithFormat:@"%@-PRINT",[[NSUserDefaults standardUserDefaults] stringForKey:@"Kiosk ID"]];
        UIPrintInteractionController *aPrintController = [UIPrintInteractionController sharedPrintController];
        aPrintController.showsNumberOfCopies=YES;
        aPrintController.showsPaperSelectionForLoadedPapers=YES;
        aPrintController.printingItem = pdfUrl;
        aPrintController.printInfo = aPrintInfo;
        [aPrintController presentAnimated:YES completionHandler:NULL];
}

Does anyone have experience with this problem and know how to rectify? What's really odd is that the actions for these hidden buttons still work; so if I tap where the print button should be, it'll print and likewise I can close the dialog by tapping the top left where the Cancel button should be.

Cheers!

p.s using latest version of IOS 11, issue occurs in simulator and on device.