I found a ruined settlement, zipped a xeno team over to it, and managed to find 5 precursor ships in orbit. The team landed safely, and the precursor fleet obliterated the delivering fleet of mine. I sent in an armed fleet to deal with them (to no avail), and retreated, leaving the xeno team stranded.
Well the brilliant scientist types, having nothing better to do started to restore stuff. And promptly became the focus of bombardment from the orbiting precursors, who evidently forgot that it was their settlement to begin with.