When mirroring lines via the effect tool at their outmost left or right side (see last screenshot), the effects takes the line thickness into account. I cannot think of any cases where this is of any use. I would expect a behaviour as shown in the second screenshot.

Same thing with elements that are pasted inside. The effect mirrors from the pasted inside object instead of the box into which the object is passted. Why? Is there one single case where this makes sense? I could not hink of any. Again the diesired behaviour is shwon in the second screenshot.

Best regards
Jürgen, Berlin