Tryndamere Gaurdian Angel + Undying Rage

In the game of league that I was in I was in the middle lane with 3 people (shaco vayne and Warwick i think) and they all dived onto me. What happened though was that I used undying rage as soon as i was at 1 health or close, that it used my ultimate, and my guardian angel. Although, i didn't revive is what happened. It did the animation and revived me, standing up but i had the death timer and was unable to control or move anywhere. The enemy could also not attack me and I just sat completely still. I didn't think to take a picture and my friends LoLrecorder wasn't going so i don't have anyway to look at it again... Please fix.

It seems this also happens with Twitch... It might just be true damage in general