What is the reason for the criticism of Al-Tha'labi, the author of the Tafsir?

Al-Tabari's Tafsir is an encyclopedic work of exegesis based on transmitted narrations (tafsir bi al-ma'thur) and an important reference for exegetes, hadith scholars, and jurists. However, it is criticized for including weak and baseless hadith, especially in the early surahs, and this is the reason for questioning its authenticity.