After the latest patch, Cruetraxa's A2 is broken. You can see it there: https://www.youtube.com/watch?v=dlYEv6IVIDQ

I have reported this through in-game tickets also. Cruetraxa now works like this against ANY champion with Unkillable buff (it doesn't matter if this buff is from a skill, passive or SP set). And before the recent patch she would just instantly kill any of them. The were not any announcement, any patch note about this. She was just silently nerfed/"fixed", the only solution to SP set we had is destroyed. 

And just to answer some people that this is as intended and the A2 description fits this behaviour. If anything, it's the description in English that needed to be more clear, because, for example, in Russian there were not any contradictions. One way or another, you can't just change something that worked for almost 2 years without any alert.