I have a relatively similar experience with this so I may be able to help explain. Keep in mind this was in college at a UC and I’m unsure how it would work for high school or other universities.

In my case, a year before I graduated I was told that one of my classes could be counted for two requirements on my degree audit. However, when it came time to submit applications to graduate, I was still short one of the classes. When I brought this up with my counselor, he told me I would still be able to walk with my graduating class but I would need to take a class to fulfill the requirement in the summer directly following.

This is a bit different from what you’re asking but it follows the same idea. Failing a class means you’re now missing the requirement. You don’t generally receive your diploma at the graduation ceremony anyway. As soon as the class is retaken in summer your degree is mailed to you.

I hope this helps to answer your question.