When using iOS Safari browser, the Certificate gets opened up in the browser instead of being downloaded. This happens when the setting: Delivery = Force Download is used.

Steps to replicate:
1. Create a course and enrol a student.
2. Turn editing on and add a Certificate module.
3. Ensure that the setting Delivery is set to Force Download.
4. Use an iOS device (iPhone/iPad). Open up Safari browser and access the Certificate module.
5. Click the "Get your certificate" button.
RESULT: The certificate is opened up in the browser tab instead of being downloaded.