Why have historians questioned whether Yongzheng was Kangxi’s chosen successor?

Historians have questioned whether the Yongzheng emperor was truly the Kangxi emperor’s deathbed choice due to the secretive and often volatile nature of the Qing dynasty's succession process.1

Following the permanent deposition of Kangxi’s original heir, Yinreng, in 1712, the emperor ceased nominating a crown prince to avoid the intense, often bloody factionalism that had previously plagued his court. Consequently, the identity of the successor was kept secret until the emperor’s death. This lack of transparency, combined with Yinzhen’s (Yongzheng's) strategic use of military support in Beijing at the time of his father's passing, led to widespread skepticism regarding the legitimacy of his ascension.213

Furthermore, historical accounts suggest that Yongzheng may have tampered with imperial records from the final years of his father’s reign and the beginning of his own to suppress information unfavorable to himself or supportive of his rivals, further fueling doubts about whether he was the intended successor.3