I used the chanter spell "If their Bones Still Slept Under that Hill, None Can Say" in a number of battles. I found that the summoned skeletons persisted after battle and would follow the party through scene transitions. At this point, I was unsure whether this was intended behaviour; the skeletons could still be commanded as usual. After being knocked out several times, a skeleton could die and would no longer follow. Invoking the spell again would dispel the previous skeletons and the behaviour would repeat. After a particular fast-travel, I believe it was from Gilded Vale to Caed Nua, the skeletons did not appear with my party. Instead, I found them standing around on the map, seemingly at random locations. They are friendly, but cannot be commanded. As far as I can tell, they follow my party everywhere, through every scene transition, spawning somewhere on every map. I tried killing the skeletons, they can be attacked but do not retaliate. After being knocked out several times they would die, but apparently turn up again as I have always been followed by at least one skeleton. I once observed, after having killed one such skeleton, its bones lying on the ground in the next map I entered. Sometimes the skeletons spawn in walls. This occured a while back in my playthrough, however I am submitting three savegames:
Raedrics Keep, I believe before the skeletons became "zombies".
Brighthollow, shortly after the zombification
Odda's House, much later in the game. At this point I am haunted by just one skeleton, which is mostly transparent.
I had difficulty attaching files to this post, so I have placed them on Dropbox:
https://www.dropbox.com/s/oxbrggf1czkt1kp/2015-03-28_00002.jpg?dl=0
https://www.dropbox.com/s/a6160mn6ktt799i/zombie_skeleton_savegames.zip?dl=0