In DBZ Buu saga, we were introduced to 2 Buus, Evil and Good Buu. But it was also showed that Good(fat) Buu is good because he had absorbed Grand Supreme Kai and his innocence is what made Buu good. But inherently, both are same beings.
Now in Dragon Ball Super, we were showed how much Buu loves fighting and trained so hard to get in shape for the Tournament.
So my question is, can this desire negate the good Grand Supreme kai had on Buu and bring his evil self back?
Negate may be incorrect term so I'll try to explain. This desire may give rise to some evil in Buu and this evil part goes to Buu's mind(We have seen this as well in Buu Saga) and breaks connection with the cocoon in which Grand Supreme Kai is held.