I have had AutoCAD crash for various reasons ...
Scenario 1
Insert a block with a polyline entity, crossing an object that can be trimmed, trim to the polyline entity in the block ... fatal error always
Scenario 2
Select an anonymous block and mirror it so it is -1 in only 1 plane. Wblock that object to a new block. Insert the new block, mirror it so the anonymous block is -1 in the other plane. Attempt to explode the block ... fatal error nearly half the time
Scenario 3
Pasteclip as block, objects from another drawing, immediately bhatch using the pasted block as part of the boundary ... fatal error 20% of the time
There are more that I have identified, but I can't recall them at the moment.