Thanks for getting back to us, alexmercier25. It's appreciated.
However, we’re a bit confused now. Are you subscribing to the subscription calendar in the native Calendar app on your device, or using a different Calendar app?
If you’re using the native Calendar app for the subscription, you’d want to reach out to the developer of the Calendar you subscribe to: How to contact an app developer - Apple Support
If you’re using a third-party Calendar, see if the steps in this article helps: If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support
If it’s still not working as expected, the issue must be in the Calendar you’re subscribing to. We recommend using the link we provided above to contact the Calendar’s creator.
Please let us know the results when you're able.
All the best.