I am having the same issues, but mine started much earlier, about the first time I entered Redcliffe. I replayed a few hours from an earlier save and thought it worked, but it happened again. It went from wiping out only unequipped items to taking my main character's bow and later my armor. At one point when I travelled to Haven it all popped back in and I was able to optimize what the entire group had equipped, but the rest vanished when I travelled again. I managed to limp through the mage choice quest and got to Skyhold, but it continues to deteriorate. I am frustrated! I had a lot of hours into it and even repeated a few hours, but now It's just too crippling to continue.
