I wonder what could cause this problem.
about 1/10 times when plugging in the AC adapter into my Zenbook, the laptop completely loses power.
I always plug in the cable into the outlet first, as I've heard that could cause problems like this.
I experience exactly same. Test please that these 1/10 are when your battery is less than 15%. In my case if battery level is low (15% and less) in 100% cases the laptop switches off after 1-4 seconds after I plug the power.
As a workaround I close the lid (to send it to sleep), plug the power and open back, but this is very annoying!
I use Ubuntu 11.10 with lates updates. It was from the very beginning. My brother have same laptop manufactured slightly earlier and had never experienced these problems.