I set up a colony on a planet with ruins and established a xenologist team on it, which did its job of understanding the stuff. Afterward, I sent an engineer brigade and some armed forces. Eventually, robotic guards were awakened, 2 in a row, and my troops lost, all dead. I quit the program (it was a great time for a pause), and when I reopened it, the colony on that planet was gone.
That's probably working as intended. Eventually, I got an event relating to my xenologist team gaining skills (1% each of the 5 members), and that tipped me off. That team was left on the colony, and even if I reestablished it, the team is not there. And of course I have no idea how they got skills gain.
The bug is, when I look at the team members in the Leaders screen, they are still part of the team and their location is at a world I don't know about. I did not even explore that system, although maybe an NPR did. I can't see that system with only SM permission. Yet there my xenologists are. Is there a way to disband a team without using the Population&Production screen?
It looks like, when a colony is lost, the teams stationed on it are sent "somewhere".