I am also running a p55m-ud2, and was wondering if you had any issues with Safari?
Everything (except iMessage) appears to be working fine on my build except Safari seems to be flashing different parts of websites that contains a cursor. It is quite frustrating!
I thought I would check with you before asking the community as a whole about this weirdness.
To be clear, if a website contains a search box, or login box, or anything that lets you type into then various sections of the page flash in time with the cursor. the area of the page seems to be random and always flashes a white box which sometimes covers the text. also edits to the text don't show properly. I have also noticed a similar thing inside the app store when I am updating software.