Chapter 12 seems to be critical of certain learned people. What specific behaviors does it warn against for those who are knowledgeable?

Chapter 12 provides specific warnings for learned individuals, cautioning that knowledge without humility can be a significant obstacle. The chapter criticizes those who, despite being "well-versed in the Vedas and Vedangas," become arrogant and use their knowledge to obstruct the path of devotion for others. This is described as being "intoxicated with the pride of knowledge." The text advises against the chaos of mixing castes and the pretense of caste pride, but also against neglecting one's prescribed duties (Varnashram Dharma) or becoming a "heretical scholar." Essentially, the warning is not against learning itself, but against the pride that can accompany it, which leads to disparaging devotion and creating spiritual blockages for oneself and others.