I think he’s referring to the top of the image, which can be seen best on post #22198. It appears to be interference or snow. Could be the result of crappy component cables. Where did you get the cables from?
And, just to confirm the configuration, you now have PS2 multi-out going to component input (AV2) on the OSSC? And you’re waiting for the audio adapter to arrive, in order to deal with the audio.
You also called it a Y-splitter. Is it a splitter or a 3.5mm to RCA adapter? Please post a link of what you bought.
Also, to confirm, you have the output set to YPbPr, and AV2 set to RGsB?