Tyler Perry -- Bobbi Kristina Did NOT Walk Off TV Show

Tyler Perry is calling BS on reports Whitney Houston's daughter Bobbi Kristina walked off the set of his TV show "For Better Or Worse" -- claiming the rumors are "not true at all."

Bobbi Kristina has a small recurring role on the show -- but reports have been circulating she called it quits before wrapping the season, storming off the set in tears.

Now Tyler -- the creator of the show -- has taken to his website to dispel the rumors, writing, "There is no way that she could have walked off the set because we have finished taping the season."

Tyler writes, "Were there tough days for her? Yes of course. Not because of the acting or any job-related issues but because of the fact that she had just lost her mother."