One of the best things about BioWare RPGs, going all the way back to the original Baldur's Gate, is the interaction between NPCs in your party. They flirt, they fight, and they talk, talk, talk, which is why some Dragon Age: Inquisition players found it odd that their companions were so very quiet, sometimes going hours at a time without speaking. Turns out, it's a bug.
Reports of the strange silence, as noted by Reddit, started popping up a couple of days ago. When it became clear that something was amiss, BioWare asked PC players afflicted by the bug who are 60-70 hours into the game to submit save files so it could analyze the problem. In an update posted today, however, it said that it has sufficient saves for now.
It would seem that one of the reasons it's taken so long for the issue to come to light is simply that players didn't realize it was a problem at all. It doesn't appear to affect the game in any other meaningful way—you can still play through from start to finish—but party members just don't talk, even though there should be some kind of interaction happening every 10-20 minutes. And if you're missing the party banter in a BioWare RPG, you're missing out on a lot.