The issue that you are having might be related to the Internet upload speed on the Slingbox location, since you are only experiencing this issue while using component cables. You can perform a speed test using the following link and make sure that it meets the requirements to stream high definition.
Try it out and post back if you need additional information.
I have that occasionally happen to me as well (on component only). It appears that it may be related to the PC that the Slingplayer is running on. It seems that the bitrate or the decoding staggers occasionally -- even on moderately powered systems. The sync issue usually appears after some audio stuttering.
You may want to try manually setting the bitrate to see if it goes away
I've recently purchased a TIVO, but I have noticed that with Verizon FIOS's DVR boxes, the audio/video would sometimes be out of sync. The fix was simple, press the pause button, and then press the play button.
I don't know why this happened but this fixed it for me. I know this might not help at all, but I'm hoping that it might.