@Fever It’s called polyploidy.
Polyploidy may occur due to abnormal cell division, either during mitosis, or commonly during metaphase I in meiosis.
In addition, it can be induced in plants and cell cultures by some chemicals: the best known is Colchicine and Gibberellic acid which, can result in chromosome doubling, though its use may have other less obvious consequences as well. It’s common to use those to “feminized” seeds and it can be the main factor for polyploidy.
So, basicly, it’s a mutant, lol .
Hope it’s a little bit clearer and confirm your suspicion