I know someone who tried to apply to a position at a large tech company and could not complete their initial forms; this person has a master's degree from a top-25 university, is soon to have a Ph.D., has studied at the London School of Economics... but left high school early to go straight to college. Date of high-school graduation was a mandatory field in their online form, and nobody at the company could come up with a way to bypass the use of that form (and entering false information, of course, is not permitted). This person may literally have to go back and get a GED after obtaining a Ph.D. in order to be able to fill out a job application.
Yeah, that's a big red flag. Sounds like the system is programming the people.
Welcome to big tech companies.
Graduation is when you are certified by the school as completing graduation requirements, and usually issued a diploma attesting to that fact. Leaving without doing so, even for higher education that doesn't require a high school diploma, is not graduation.