Posting yet again to help those experiencing the banter bug. And in case Bioware is still reading this, yes, your game is bugged. The Western Approach is completely broken. If you determine why random banter does not occur there, you will probably isolate the root cause.
90hrs into my 4th playthrough. The below has worked for me to get banter. BTW, I did 2 playthroughs on PC and 2 on PS4. The banter bug happens on both so is platform independent. That means it is all in the game code and has nothing to do with our hardware.
1. Stay offline.
2. Always fast travel to zone from war table.
3. Click off the yellow stars by all quests, codex and inventory entries.
4. Do not go to Western Approach if you want to hear banter (note - I have found two places there were random banter does occur: The Tevinter lab and Gate of Toth on door mechanism side. Otherwise, the only banter you will hear is triggered.)
To Bioware's post about how banter should work. If that is correct, then my experience is further proof that this functionality is broken.
1. You state that banter will not occur during combat.
Not true for me. I have had conversations start and continue during combat.
I have had conversations start at end of fight but while we were still in combat stance.
2. You state that banter will occur about every 10-15 minutes.
Not true for me. Even before I did the workarounds during my first playthrough, I would get a rapid fire experience. Every 3-5 minutes. Then nothing for hours.
For those that do the workaround above, if you notice the banter has stopped no matter who you have in the party, I may have found the root cause. I found this in someone else's post. It may relate to the number of open quests. Like there is a threshold, so once you reach a certain number the banter just stops. If this is true, this is also a coding defect. It would explain why clicking off the star helps banter return. The star probably is a part of the open quests or item count.
I work from home so I can leave the game on for hours. I was having good banter then it stopped. Counted my open quests and had 25. I parked my party with companions who had rarely quested together in a safe area that usually had banter. There was none at the 10/15 minute mark so I thought this confirmed the quest count issue. However, at about the 33 minute mark, the banter started. It continued every 10 minutes.
This was still unusual since normally my banter would start within 5-10 mins of entering a zone or loading a save. My suggestion to those that do the workaround but still have no banter is to reduce the number of open quests. 15 or less may be a safe number.