Following the winter update, I requested my companion's calling card, thinking I would get an explanation or something first, which I did not. My companion disappeared, leaving a survivor box that only contained the quest item I had previously given her to carry, and her calling card was added to my inventory. Hovering over it gave me the desired explanation, and I figured I could resummon her whenever. However, after traveling to a different realm, when I attempted to resummon her, the card was removed from my inventory but nothing else happened. My companion did not appear in that realm, nor my respite realm, nor any of the realms I've been to since. Her card has not been returned, nor any of the items she was wearing or equipped with.
Bump, I guess? I am also having this problem; however, I am a hoarder of loot. As such, this does impact my gameplay significantly. I am still capable of progressing through the game with increased difficulty due to the lack of my Recruit.