For a PKM to be legal, the handling trainer must have a memory, with a trainer name matching the save file that trades it.
The PKM must have a memory with the trainer it leaves from, hence it arriving to you (the OT), with details of being with the previous trainer (HT), which happens to be the sysbot.
Go do a tradeback with someone else if you're paranoid about someone recognizing you got it from a bot. Or, just be honest; there's nothing wrong with using injected things for personal use.