It does? How often?
If you look at the number of cases of dropped dead suddenly over the past 3 years, it’s obvious it’s very common. Nothing out of the ordinary at all.
The annual pre-Covid mortality rate for a 20-year-old female was 0.0439 percent for "all causes".
No, this does not happen "all the time".
"Died Suddenly" used to be extremely rare, especially for 20-somethings. Now it isn't.
Definite answers are not forthcoming. Choose whatever explanation you prefer.