Well the random child showing up as your Sim's child is an older glitch that I feel a lot of us thought was fixed.
Whenever my Sim would travel there was always a minor chance that they would get an illegitimate child (almost literally illegitimate!). Even my teen sim accidentally wound up with a child.
The two things I have concerning that glitch though was:
1. I haven't seen it in maybe a year... or two.
2. I haven't actually played World Adventures hard core in maybe a year, or two.
If you get what I'm saying.
There's a good chance it's a similar glitch.
Edit to say: it could be the Time Machine as well. Makes more sense now.
However the Simbot thing was meant to happen that way. Seeing as your sim CREATED the Simbot it is assumed your sim would take to it as it's child. Unfortunately it's stuck that way. My boyfriend found that one out the hard way as he didn't want his Sims to have any children either. After making a Simbot he claimed he felt it was awkward and now he felt his Sim had a strange responsibility.