How do Ibn al-Mubārak’s praise of ʿAbbād’s piety and warning against his hadith fit together?

Narrator Criticism, Integrity and Precision: Standards of Scholarly Appraisal

• The statements necessarily contradict one another
• Piety automatically establishes the accuracy of every narration
• The warning concerns every aspect of his ethics, not transmission
• Some piety can deserve praise while his hadith precision remains unreliable