Now it's skipping past other data for reasons I can't figure. This time it's skipping past a whole 16 bits. Is there some sort of long-word alignment, too?

Edit: Nope. I've verified that it can read odd numbers of 16-bit blocks (at least in other cases occurring milliseconds before). I've even tried changing it so that it's no longer MSG_PEEKing at the first byte, but reading two bytes and holding the second in a buffer for later use. Still didn't fix it. And I'm watching the data fly across the wire with a packet snooper, so it's not like I'm expecting data that's not really being sent. This is being a royal pain.

Edit edit: actually, looking at it some more, I can read in odd bytes in other places as well. This makes no sense.