PS4, Deluxe, physical disc - only other game glitches seem to be the dialogue wheel, otherwise game runs smoothly. 30 hrs+ with only 15-ish instances of banter, most of them have only started in the last two hours of gameplay since Dorian was introduced. (It had been completely silent, regardless of the region, for about 10hrs beforehand.) Bull will only talk to Dorian/Sera, Blackwall will only talk to Sera. Varric/Cass/Solas had three banters in the beginning, but they won't talk to each other or anyone else, and Viv/Cole have only had one banter each. Everyone is at good approval.
Fallow Mire: x2 (would only fire for Sera/Blackwall) - 3hrs there?
Storm Coast: 0 (have tried multiple party combinations.) 4hrs?
Forbidden Oasis: 0 - 1hr.
Hinterlands: x? - 16 hrs? I'd had no banter in the Hinterlands for ten hours (tried many different party combinations, and took them out for long periods of time) until I took Dorian out for the first time post-Skyhold - he triggered some with Sera, and then had some with Bull, and then Sera/Bull again.
Emerald Graves: x3 - 40 mins. The only semi-normal banter fire I've had in the entire game. Again Dorian and Sera, with Dorian continuing the banter with Bull on from the Hinterlands. Like in the Hinterlands, it seemed to be normally timed banter, with a few minutes between each comment.
Crestwood: x0 - 30mins, no banter. Hoped my game was fixed after the Emerald Graves, but no - Dorian wouldn't trigger Blackwall or Varric.
I think it's also really important to emphasise how little music seems to be triggering as well, I don't know if it's related to banter glitch. 97% of my time exploring the areas would be in silence, with only ambient noise for company - a very lonely experience. My first two vists to Val Royeux were completely silent, but at my next visit Val Royeux is filled with constant music. I'm not sure what's the default? Emerald Graves had some as well, but I had to go out into the middle of the desert in the Forbidden Oasis to trigger any music. None in the Storm Coast, a little in the Fallow Mire, and only about three minutes worth in total for the 16hrs I've spent in the Hinterlands. I'm not sure what is intented?