Containers too? I'll keep looking for strange containers, maybe they are default state when something is corrupted.
I looked at the mysterious "8" objects, before they changed into baskets, and their sprites look like broadswords (i.e. swords with red handle). As if there were several broadswords lying on the map, but glued to the forest. I'll admit than when I've found them first, I thought about reverting a save, because it looked like a corruption, but then decided that too I would have to go in time too far, maybe even over a year (bandits were killed in April of 3rd year, and the full transformation occurred in 4th year).