If you start synth-ascended. Because you're treated as in "servitude" when the game starts, it prevents you from getting new leaders at the start of the game until 5 years pass. This can be quite a big handicap for early game exploration.
I'm not able to reproduce this. My main species has full rights. On game start the species is at assimilation. But after 1 day it is corrected. I can recruit leaders no problem.
https://steamcommunity.com/workshop/filedetails/discussion/3163759042/7260435610011367539/?ctp=3#c7026264603294086002