The old code delayed duplicating till the end which means the
rotate/mirror would affect the original, and then be duplicated
leaving the original incorrectly rotated/mirrored.
Block rotate and mirror now work like they do in Pcbnew (that is
they're treated as part of the block move/duplicate/whatever
rather than finishing it).
Fixes: lp:1780794
* https://bugs.launchpad.net/kicad/+bug/1780794