Same experience today. Had done my MDAC beforehand. Been to KL before but not on this passport which is 2 months old. I had thought I would need to go to a manned desk to register for the egates and have fingerprints taken, but on reading this thread I just went straight to the e gates and all worked fine.

for the mdac I can’t see you can do it more than 3 days before - the form only allows you to select an arrival date of today, tomorrow, and the day after. All other days are greyed out.