That is what I was thinking myself.  Usually the reporting is separated into separate boxes.  In this case the Payer issued the both codes inside the same box instead of utilizing the available secondary box.  Thank you.

"The code M1 indicates that your loan was paid off with an offset distribution from the retirement plan, effectively a distribution from the plan paid to you that was immediately turned around to pay off the loan."

Someone took at loan from their employer retirement plan account, and instead of paying it back, they are now charged with it as Distribution.