[Testing Suicide botting] Running 4 RaF in the same group 2 banned 1 suspended

Hello, i REALLY don't understand the logic of Blizzard
I bought 4 brand new battlechests to test for how long i could suicide bot aka. bot 24/7 They've been running for about 2 weeks now. 1 hour ago all running the same dungeon in the same group 1 was left unharmed 2 got permanent ban and 1 got 72 hour suspension - how in the world would this ever make any common sense? Please explain

Was the game account created after the 13-May-2015 banwave? - Yes 2 weeks ago

SILVERMOON - EU, Alliance

Did the account have any previous suspensions or bans? Nope none of them

How many (average) hours per day did you bot? 24 hours for 2 weeks

What estimated percentage of the time did you supervise your bot? 5%

Was your account involved in gold selling? Nope

Did you use any non-Honorbuddy bots with this account? If so, which ones? No i did not

Did you use any H4cks, Che4ts, or mods with this account? If so, what are their names? No, not at all

Do you have any observations about the event you'd like to share? Read the first 3 lines