Edit: Sorry it was me. I changed headphones setting to mono to check it.

Did you update videos? suddenly I'm hearing significant wobbles. What I've been hearing was more like a tone than wobbles.
Nope, YouTube doesn't allow updating videos... :)
Be sure to check each earpiece separately, and make sure you only get a steady tone from each one. Wobble should only appear when listening to both L and R.
정태훈