If you complete a research task, but don't catch the pokemon immediately (instead running away and catching it later) the Pokedex counts it as having seen two Pokemon. Once when you ran away from it, once when you catch it. It does not do this for wild pokemon.
I discovered this during the event, when suddenly my perfect record of catching Misdreavus was gone. I used to berry every wild Misdreavus i saw to ensure none would run away from me and i could maintain that perfect record.
This is quite disappointing for me.
This was something people noticed with Spiritomb. I saw someone's screenshot where it said they had encountered 6 of them despite the obvious fact that you only encounter one.
You wanna talk about disappointing streak kills, let me tell you how out of 50+ Mewtwo encountered only one has run away from me right around the upper 30 mark.
It only does that if you haven't seen the Pokemon registered first. I'm currently 6/6 on Shinx for example, seeing one in a gym won't change that to 6/7. Pachirisu is something I haven't even seen, if one dropped in a gym I clicked on it would then be shown in my Pokedex as 0/1. From this point on at best I would have a catch record of [Seen - 1].
