Why are there contradictions between Mahabharata and Bhagavatam?

From Maha Raas Prabhu:

I got see the Mahabharat by Krsna Dharma Pr. I was  astonished to find that the description of duel between Bhima and Duryodhana given there says that Lord Balarama interfered and wanted to kill former and Lord Krsna practically gripped Balaraji.

Whereas  SB says that after giving detached suggestion to warriors, Balaramji left for Dwarka. Kindly clarify.