Suspicious behavior of players/AI???

So i have been wondering since yesterday. I usually play Coop vs Intro AI games to get my first win of the day reward, when I don't have any time for 5v5PVP.

And yesterday happened something weird as I joined a Coop Intro AI match. First suspicious action I noticed was the 3 instalocks of 3 certain champs. I mean when I join the champ select late due to PC performance issues the timer to select a champ has already ticked down for a few secs. But I joined instantly and was able to pick a champ at full timer. However the 3 instalocked champs were Caitlyn, Tristana and Sivir. All three of them had Heal and Barrier as summs (maybe low lvl player?). Ingame they went midlane and were showing AI behaviour, such as standing brain AFK under the enemy turret and attacking enemy minions. They weren't even chatting since i tried to get them chatting.

Today I experienced the same. I just played a Coop vs AI match and encountered again two instalocks, Caitlyn and Tristana. Same behaviour ingame.

After the game I checked their profiles and something I noticed was that all these accounts have the same summoner icons and their match history was filled by the same champion and gamemode.

The names of these accounts were different from them yesterday and i don't know how to feel about that... secretly implemented bots in matchmaking? Third party program?

If you have an idea on what is happening or if you have encountered the same let me know pls.

(Account names: if I am allowed to put the account names on this post let me know)