Soraka Bot (Custom Game -Summoners Rift- 1v1) stops doing anything after bringing her below 600 HP.
I got this bug for multiple Champions whilest testing out the Fanatic skins.
(Summoner Spells: Flash, Revive)
Steps to experience this Bug:
1.: Create a Custom Game on Summoners Rift and select Soraka as a beginners Bot
2.: Pick any Campion with a Fanatic Skin (dont know if the Skin matters)
3.: Try to catch Soraka and bring her below 600 HP
4.: Soraka will stop moving, casting and doing auto attacks.
Luckily i was recording the new Fanatic Skins so i got the bug on video too. If yot want to take a look: http://youtu.be/CxgMlIm4dj0
Hope i could help.