@virtiw, welcome
This back-and-forth communication is referred to as "reciprocity", a common deficit in ASD.  I also have this issue, but how it manifests itself is the "inability" to just naturally come up with things to talk about, with the exception of say, a special interest.  I can stand up and lecture all day at the head of a classroom of students, but to sit across from someone and simply have a "normal" back-and-forth conversation, I really struggle, and if I try, it feels a bit "forced" and awkward.  I simply cannot come up with appropriate "small talk" with anyone.  If the other person wants to take the lead, I can respond, but there's another component.  That is, I am not interested in people, and a lot of neurotypical conversation is about people.  So, I am not interested in it.  I, on the other hand, am interested in ideas and things, and most of the people around me are not.  So, again, if I bring up a topic, they have nothing to add, and I can end up monologuing when it is not appropriate to do so.  Group conversations are pretty much a "no-go" with me.  I don't have the skills to know when to jump in and out of the conversation without it being an awkward, embarrassing mess.  Sure, I can follow along in my head, but I can't get a word in, at all.  The conversation tempo is typically too fast.  By the time I do have something to add, the conversation has often moved on to another topic, so I just sit there quietly, smiling and nodding my head, following along, but not participating.