Apple Watch magnetic bands affecting with ECG reading?

I have been noticing lately that the Apple magnetic closure bands affect whether or not I can take an ECG reading. I have cleaned the band, watch, and digital crown, and still, the problem persists. I have also switched back to the sports band that came with the watch originally, and the issue seems to be fixed. And sure, I could just use the sports band, but I bought the magnetic bands from Apple because I like the way the look.