socket.c:1100: unexpected error

I've been seeing a few of the following errors lately.

Jan 26 17:49:55 bugs named[744]: socket.c:1100: unexpected error:
Jan 26 17:49:55 bugs named[744]: internal_send: 67.173.252.243#0:
Invalid argument
Jan 26 17:49:55 bugs named[744]: client 67.173.252.243#0: error sending
response: invalid file

I goggled a bit, all i could find was others reporting similar
instances, but i never saw a definitive explanation. Does anyone have a
clear explanation of what causes this error? Specifically, is it a
valid query gone bad, or is it suspicious activity?

Bind: 9.2.1-1

Thanks,

-Jim P.