AM Broadcast station coming in on shortwave

This week I put up a new random/long wire antenna. It's 107 feet long and 18 feet high. It has a 1:1 balun at the end that comes into the house on 30 feet of RG8X coax. I only use it for receiving MW and shortwave. The antenna works fine and is definitely an improvement over my old antenna. I'm out away from any large city AM radio stations. Boston is the closest at 75 miles. There are several low powered AM stations about 20 miles away.

But I have noticed something odd. My Tecsun PL-880 is...

AM Broadcast station coming in on shortwave