I´m new here so don´t bash me. 
In my first playthrough, i had normal party banter at the beginning. Can confirm that since Cass and Varric were talking all the time in the Hinterlands. Then, when i started to advance in the game, the thingy started as well. No banter anymore. After the Patch 2 and with the magic of the "Go to Val Royeaux etc", i had some strange behave in the banter system. Sometimes was long and silent, sometimes my companions were bantering a lot, and, the weirdest, sometimes, when it was glitched or stucked or whatever, i had a strange solution: Go fight. After every fight, common fight, sealing rifts, some banter was triggered. And again, some hours into the game with my party talking, silence again, then banter again for some creepy unknown reason. Can say that is a lot of randomness in this thing. Now, gladly heard that the randomness seemed to be the problem for some people and Bioware got it. Downloaded the patch. Started playing. Not a single banter in 5-6 hours of gaming. Changed companions, changed places, changed... Meh. So, i´m a "little" confused and worried: Did the patch worked for those who had the problem cause of its randomness but broke it for those who had it for some other reason? Jesus, my head is a mess. Gonna play some more and pray for the best.
Btw, love you Bioware, and i know PC users, well, we are a pain in the ass sometimes. But not without any reason. Keep the good work! (And sorry if my english if it´s "buged", not a native english speaker) Much love.