Rashi notes that Korach is called “the son of Yitzhar, the son of Kehas, the son of Levi”, but not “the son of Yaakov.” This is because Yaakov asked that his name not be included as part of the machlokes, as is stated (Bereishis 49:6): “Let my soul not enter their secret, and let my honor not join their assembly.”
Sefer Devar Yisroel (Parshas Vayechi) quotes his grandfather, the Rebbe of Kuzmir zy”a, as asking what the big “secret” of Korach was that Yaakov did want to be a part of. He explains that Yaakov knew that Korach’s arguments certainly were not solely based on his drive for power and haughtiness. He certainly had a secret reason why he felt that this was the way to serve Hashem. Still and all, he asked not to be involved in this secret. Even if this secret involved some aspect of avodas Hashem, he wanted nothing to do with it if it would lead to machlokes.”