First, the scythe sometime sticks after you've been farming, making the screen hard to see. The scythe is inactive, so it's a glitch and not a catastrophe. Returning to farming clears it.
It is possible to unload a train before it reaches you, no serius impact on playability but exploitable when on tight deadlines.
If you are relocating a narrow building, the outline can forget which way the building will face when placed.