double messages from Yahoo group

Hey, I'm leading the Browns class and am getting double messages in my inbox from that group. Everything comes through twice -- other people's posts, my own posts sent from my email, and my own posts posted through the web site. I get individual messages from other groups too, but this is the only groups where this seems to be happening.

I can sort through it but it's annoying :-) Any hints on what I can do?

Thanks,
Val