Picking up dropped birchnuts from burnt trees in city aggros guards

I spawned a poison birchnut from chopping tea trees that I planted in Swinesbury. A pig guard set the crop of trees on fire, and one of the birchnuts dropped a seed. When I picked it up, it drew aggro from the guard and he killed me. I'm not sure if this is intended, but it seems wrong that a dropped item from a tree that I did not chop/burn should count as stealing.