Uplifted Species Gone?

[ebelek]

So I find some pre-sentient aliens in my space and I was like lets uplift them. I sent a colony then started a project to uplift them. The project completed and they became uplifted. To this point there was no problem then there was 3 events to give them some ethos and I was like ok lets give them some ethos. During these events I was looking other things in game then checking them. Then they gone from my space. There was no events or anything to tell me this. The planet became empty. In species or contacts tabs they do not exist. I am flabbergasted now. Is this thing normal or a bug? Sorry I got no screenshot for this because I was looking other things then I was like lets put these guy in to other planets and look at their space to find an empty planet.

edit : So I tried to recolonize the planet because some of my pops migrated there even though my planetary capital gone and I do not control the planet so I recolonized it and game deleted them. Then I tried again and game deleted them again.