My wife got a 1099-R Form in the mail. She took out a 401K loan for $3300, and is paying it backwith weekly deductions from her paycheck. Does this need to be reported?

She's been paying the loan back and is not in default on it. Should she even have gotten a 1099-R for a loan?  She's had one in the past and never got a 1099 for it. Is this a mistake, and if so, how is it corrected?