[Eddie Mendoza]

Two weeks ago I did the 8.1 update, but before I could play with it I dropped the phone and broke the screen. I sent it to Palco to get fixed. Now that I got it back the screen sometimes randomly starts to move on its own and launches cortana, if i turn the screen off and immediately back on it responds as normal. Is this a 8.1 issue or a bad Palco repair? Anyway to revert back to 8.0? Thanks for everyones input!

I've tried the following with no fix:
Set screen to medium Brightness with normal touch
Set screen to medium and auto with high touch sensitivity
Factory reset of 8.1
​

[Ramin Hossein Zad]

It has nothing to do with 8.1
i had this problem from the day i got my phone
it's better when it's not in it's flip cover but when i place it in the cover it just goes crazy and does whatever it feels like doing
i do believe it's hardware and since i live in Iran and there is no official nokia retailer i'm stuck with it

[LucasLumia]

I live in Argentina and it happens to me too but it happened to me exactly when I installed 8.1 preview so I think it might be it. Haven't dropped it even once.

[Ma Rio]

It's the digitizer, I dropped mine and it went crazy.

[badcat]

You can revert back to 8.0 using the Nokia Software Recovery tool. It sounds like the digitizer though.

Nokia Software Recovery Tool updated with support for Windows Phone 8.1 and more! | Windows Phone Central