linked Shapekey actions weren't getting copied when their owner data was. This was due to the IMO totally convoluted way in which the duplicate action flags have been set up: - the function to copy animdata takes a param to specify whether actions are copied or not, but this is never touched (i.e. this always just gets FALSE passed in) - instead, we jump around in hoops later figuring out whether the userpref wants copying to occur, then fixing up the links IIRC, part of this may be due to a desire/need to not duplicate actions when dealing with NodeTree copies for multi-threaded rendering, but at the expense of complicating everything else.