I know I have an adventurer former hireling near my homestead, and I fear he'll drown once it thaws, as he's wandering around on the river for a fair bit. I dismissed him a few kilometers to the south, which is in the general direction of the village he was hired in.
However, this is another strange hireling issue:
3 months ago my character hired a large number of assorted villagers to deal with robbers, and I dismissed them a few kilometers south of my homestead (again, in the general direction of their respective villages). However, I just ran into "a rem hunter", zoomed in, and saw a large number of characters that most probably was the group I had employed. I looked around (on the zoomed in map), and they were suddenly all gone, but there were very fresh footprints, and I followed one set running parallel to another set, until it suddenly stopped, and at that time I followed the other set. I made a save after following footprints for a fair distance, without catching up with anyone (I'm not sure if the save was before or after running out of the first set of footprints).
It's probably unrelated, but I was unable to find any quests on my last attempt, visiting about 8 settlements over two days.