Horizon Needle can't embark my capital

[vainglory]

Have a massive empire on a large map, finally cleaned up 100+ colonies with the Horizon Needle and vassalized the last few sectors, and now all that remains is the synaptic lathe (which has a single pop I can't remove) and my capital, neither of which I can embark from. Anyone else experience anything similar?

[vainglory]

Alright, looks like it was because I traded away my last colony that I accidentally acquired during a war instead of embarking it. I suspected that might be it, but couldn't make a new colony since having the horizon needle active prevents making colony ships. I got war declared on me by a single system empire though and once I conquered *that* planet and embarked it I got the popup allowing me to progress and embark my capital.

[riderkick]

I had to tell it to embark on my capital multiple times before it did it