I have had a number of problems working with the attached document (mouse stuff square2.afdesign) which contains 4 placed pdfs. Firstly, when I export the document the resulting pdf expands one of the subfigures so that part of it (top right subfigure) is covered up (mouse stuff square2.pdf attached). Secondly, when I return to the main figure after working on a subfigure the resulting canvas is black and to recover the figure I have to open a new artboard (this recovers the figure) and then undo the creation of the new artboard. then all appears okay. I suspect these problems are related.
mouse stuff square2.afdesign
mouse stuff square2.pdf