Rishi Vyasa apart from compiling the Vedas and the Puranas is known for writing the Mahabharata, Srimad Bhagavatam and the Devi Bhagavatam. However an article showed me numerous inconsistencies and contradictions in the Mahabharata and the Srimad Bhagavatam. Some of the contradictions are mentioned below:
ete cāṁśa-kalāḥ puṁsaḥ kṛṣṇas tu bhagavān svayam | indrāri-vyākulaṁ lokaṁ mṛḍayanti yuge yuge ||(SB 1:3:28)
All of the above-mentioned incarnations are either plenary portions or portions of the plenary portions of the Lord, but Lord Śrī Kṛṣṇa is the original Personality of Godhead. All of them appear on planets whenever there is a disturbance created by the atheists. The Lord incarnates to protect the theists.
Then the Mahabharata states:
yas tu nārāyaṇo nāma devadevaḥ sanātanaḥ | tasyāṃśo mānuṣeṣv āsīd vāsudevaḥ pratāpavān | śeṣasyāṃśas tu nāgasya baladevo mahābalaḥ | (MBH. 1:61:90-91)
And he, called Vasudeva, endued with great valour, was among men a portion of him called Narayana–the god of gods–eternal. And Baladeva of exceeding strength was a portion of the Naga, Shesha
The Srimad Bhagavatam also calls Balarama an incarnation of Lord Vishnu. I don't have the relevant quote right now to show that.
Then it seems in Mahabharata that the 18 major Puranas were already composed:
aṣṭādaśapurāṇānāṃ śravaṇād yat phalaṃ bhavet | tat phalaṃ samavāpnoti viṣṇoḥ nātra saṃśayaḥ ||” (MBH 18:06:97)
One devoted to Vishnu acquires (through reading this Mahabharata) that merit which is acquired by listening to the eighteen Puranas. There is no doubt in this.
However, in the Srimad Bhagavatam it is said that Vyasa even after compiling the Vedas and writing the Mahabharata was still sad and Narada visits him to write the Srimad Bhagavatam:
jijñāsitaṁ susampannam api te mahad-adbhutam | kṛtavān bhārataṁ yas tvaṁ sarvārtha-paribṛṁhitam || (SB 1:5:3)
[Narada said]: Your inquiries were full and your studies were also well fulfilled, and there is no doubt that you have prepared a great and wonderful work, the Mahābhārata, which is full of all kinds of Vedic sequences elaborately explained.
śrī-nārada uvāca | bhavatānudita-prāyaṁ yaśo bhagavato ’malam | yenaivāsau na tuṣyeta manye tad darśanaṁ khilam || (SB 1:5:8)
Śrī Nārada said: You have not actually broadcasted the sublime and spotless glories of the Personality of Godhead. That philosophy which does not satisfy the transcendental senses of the Lord is considered worthless.
yathā dharmādayaś cārthā muni-varyānukīrtitāḥ | na tathā vāsudevasya mahimā hy anuvarṇitaḥ || (SB 1:5:9)
Although, great sage, you have very broadly described the four principles beginning with dharma, you have not described the glories of, Vāsudeva.
tvam apy adabhra-śruta viśrutaṁ vibhoḥ | samāpyate yena vidāṁ bubhutsitam | prākhyāhi duḥkhair muhur arditātmanāṁ | saṅkleśa-nirvāṇam uśanti nānyathā || (SB 1:5:40)
Please, therefore, describe the almighty Lord’s activities which you have learned by your vast knowledge of the Vedas, for that will satisfy the hankerings of great learned men and at the same time mitigate the miseries of the masses of common people who are always suffering from material pangs. Indeed, there is no other way to get out of such miseries.
I have given the 2 major contradictions between the Srimad Bhagavatam and Mahabharata. There are more contradictions apart from these. You can read all of them in this article. So why are so many contradictions between the Mahabharata and the Srimad Bhagavatam?
P.S. I have got all of the above verses from this article. Apologies to anyone offended by my question including to Krishna, Vyasa, Chaitanya Mahaprabhu and to my fellow-Vaishnavas.