no, im aware of this and usually leaving enough space between them. i wouldn't complain, if its so obvious.
it's annoying if you queue burried fusions with your base builder and come back to see he builds the fusions on top the half or less terraformed place.
it just stops the 3-4 click deep terra at 1 or 2 clicks and builds the building.
if there would be missing space (red corners as you mentioned from other buildings) it wouldnt build the fusion.
Sorry for the typos, but it's quite late.