I think some of these might have been mentioned before. Sorry for any redundancy.
Aquaduct channel pathfinding:
Dwarves seem to treat the aquaduct channel of both water and magma as empty. I've had a mechanic drown trying to install a floodgate mechanism next to the channel, then several dwarves leap into (the then) magma filled channel trying to get his stuff before I managed to seal off the aquaduct with doors.
Siege Operation spam:
Building a ballista and having no ammo produces a potentially machine crashing message spam about no ammo. The game crawled to a halt and it reached over 14,000 messages before I managed to locate everyone with siege operation on.
Chasm Pathfinding
This one was kind of strange. I thought breaking the chasm refuse pathfinding involved multiple bridges- I built only 1 5 x 5 bridge over the chasm (didn't build any others over the chasm before it) but I still got the 'can't find path' spam when I set to chasm skulls.
Goblins 'Trap':
I'm 90% sure this is NOT a bug, but... a couple of goblins killed an elven caravan near the edge of the map in an old game of mine and just hung around it, waiting for my dwarves to pick up the cloth and armor that was dropped. I sealed up my fortress for around 3 seasons I think, before deciding to venture out to try to kill them with disastrous results. I had my soldiers run at the goblins 1 at a time, making for a slaughter line that anhilated my army.
Just wanted to know if goblins hanging around dead caravans is a bug, or a nasty little trick they have for the item-greedy dwarves~