Hi James,
My understanding is that Inbound/Outbound can mean that a conversation had segments that were different directions, even if the call was not an "outbound" call in the traditional sense:
"The direction of the interaction. Inbound/outbound indicates that the conversation had multiple parts that were of opposing directions. For example, an outbound call to a queue’s external IVR contains both inbound and outbound segments."
https://help.mypurecloud.com/articles/interaction-details-report/