I'm receiving, for some number of weeks, many duplicate copies of e-mails sent from addresses similar to 

<MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@arrl.org> 

Is anyone else experiencing this duplicate copy bombardment?  What is the reason for these e-mails, and how do I arrange to no longer receive them?

Thanks, Bob -- W6RGG