I had similar problems when I first started on exo-planets. Initially I took longer in getting underway than I had anticipated and hence did not have enough egress lead in time, sometimes I would even start imaging after the egress point. This past week the auto guider has decided not too auto correct tracking for some reason, even though I had changed nothing from the working sessions before. Irrespective of any number of calibration sequences I now make it goes of on it’s drunken man’s walk about.
Incidentally, which exo are you trying.