The functionally correct code could be rejected in PR for many reasons other than style:

1. Solution under-engineered/over-engineered. 2. Code is hard to read or comprehend. 3. Design/Archtecture lacking. 4. Principles decided upon by team not adhered to.

These are just some of the reasons I've rejected functionally correct code before.

To summarize, in any software engineering course you learn that there are other metrics used to evaluate code other than correctness (maintainability, readability, scalability, portability, efficiency etc.)