The reason why they took this route was not explained in early narratives (at that time the existence of La Canela was still taken as fact, so no explanation seemed necessary). The reason became clear only on the publication of Pedro Cieza de León's history, which remained in manuscript form until 1871.
The explanation for their route selection wasn't provided in early accounts (La Canela's existence was still considered true at that time, so no need to explain). The reason became clear only after Pedro Cieza de León's history was published and remained unpublished until 1871.