it goes like this: at totally random, wether im looking around some settings on systemconfig, unpacking a compressed file or just browsing something on Dolphin it just jump back to the default oxygen (i'm using the Obsidian Coast scheme).
but it doesn't just switch back, the current theme i'm using stays selected on the systemconfig screen; the only way to fix this is choosing other theme and then back to the one i'm using.
Screencast of the bug
F16 x64 on a GeForce GTX 560M with propietary drivers