DVDs have dashes at top of screen when playing on blu ray player?

[Mikemovies]

I'm still buying some DVDs, mostly old documentaries that will never make it to blu ray. Right now, I am on a boxing kick, for example.

I wonder if someone could help me solve an issue/concern please? It comes when I play them on a blu ray player.

A few DVDs, not all, I pop in to my Oppo (and my Panny too) have dashes across the very top of the screen, and sometimes something across the bottom, but mostly the top. Please see 4 screenshots I attached.

Is that indicative of a wrong setting on my blu ray players, perhaps related to playing DVDs, or is that simply the now very old DVD technology of those discs not being completely compatible with modern blu ray players?

It's not awful, but a bit annoying. Sometimes I zoom in a bit to get rid of them but in a perfect world I'd rather resolve the issue.

Thanks!
ML