When using a decision diamond the process ends in two different places, which each have a distinct output. Unfortunately when entering an output there is no way to define which part of the process produces that specific output. The map shows both outputs flowing from both ends of the process.
I can definitely see the value in being able to select which output you would like to surface your content in. We don't have this on our roadmap right now, so we'll monitor this idea for interest from other customers.
therefore, please vote for my request / suggestion as well: https://nintex.uservoice.com/forums/919189-7-nintex-promapp/suggestions/45543496-increase-flexibility-of-what-you-can-do-with-decis
Thank you very much in advance.