I think Roxbury 2 might be on something there, it could be related to virtues gain, but just not activated yet ? I just tried on live to gain compassion by doing prisoner escorts , before and after I placed the compassion fragment at the shrine, and I didnt see anything different with the gain from escorts. I also tried to res someone to see if it buffed the compassion effect to hit point after a res, which again , didnt seem to increase the virtue effect. My target resurected normally at 40% hit point (I was follower compassion).
My second theory on the fragment if its not related to virtue gain/effects, it could be some kind of keys to open a new encounter pretty much like exodus you need to wear 4 different keys.
Anyways, We shall know soon folks