Weird bug happened when my soldiers tried to engage a giant bat that had been harrassing my dwarves...
An armorer arrived in an immigrant wave. He was immediately harrassed by a giant bat, which eventually left him wounded but alive. He was carried inside and dropped on a bed for a season or so.
I removed the bed because it was in the way of a planned rearrangement and he was taken to an alternative bed. The giant bat then returned and harrassed another dwarf (with the armorer still inside and resting). Meanwhile I assigned the bed he was in to him and added a few extra niceties to the room to keep his mood up. The bat returned and my soldiers engaged it. Then Spring arrived.
From the moment Spring arrived I received a continuous stream of messages that my armorer was "cancelling rest, interrupted by giant bat" despite being several Z levels away from the action and a fair distance away along the horizontal. My soldiers engaged thebat but... oddly.
I had them set to chase opponents and to harrass dangerous wild animals. Despite this, when the bat descended to ground level to engage one soldier, the others all just stood there, none more than 1 tile away, watching the action but not joining in. They continued this regardless of whether I assigned them to be stationed on the tile the bat was on, next to it, near it, or whatever.
There are 2 giant bats on my map and the soldiers ended up engaging both of them repeatedly over a period, but every time whatever happened, and whichever bat it was, they behaved the same way. And through it all my armorer was continually being "interrupted" by the giant bat, despite being so far away.
After the bats escaped YET AGAIN I removed the armorer's bed and locked him in his room. After a moment he got up and sat in the corner, dropping a spot of blood. When I moved back to where my soldiers were stationed there was then a drop of blood on the area they had been fighting the bat, which had not been visible before my armorer's bed was removed. The giant-bat spam from the armorer stopped and did not restart after he moved to an alternative bed not assigned to him.
I am not sure what the key factor was in making my soldiers bug out. The change in season, the bed being assigned to my armorer or the bat engaging soldiers. But either way it was frustrating!