fmg: for me i just use slider on side of device to turn screen off and back on straight away. running thumb as estel reiterated for me and like him i only update when a new thumb release comes out. i've only got one device so i find the delay between cssu-t and thumb good for finding any major issues.

only happened once yesterday, as soon as a new web page finished loading. page was a game faq so a txt file (~25kb) with a little js embedded for scrolling. didn't have answer i wanted so can't remember page. as estel said, it is random but my device usage pretty much centres around web browsing so only place i've experienced it

Latest thumb
KP52
Swap on SD (2x1gb on 64gb sdxc managed with flopswap)
Desktop widgets pretty much stock with a few bookmarks scattered about.
Transistions.ini from cssu
Orientation lock applet installed and locked to landscape
only 1 browser window with selected page and microb bookmark window open.