@leocg there are a lot of pages with the same issue. I have:

Windows 10 19041.508
Opera GX 71.0.3770.175

And I can show you something interesting: If I take the screenshot with the Opera native tool I got this:

But if I do it with the Windows Print Screen, I got this:

Here's another example:

Opera native tool:

Windows Print Screen:

Here you have the links:

https://play.google.com/books/publish/
https://galileo.filos.unam.mx

@Kururu Yes,you are right. I tried the xemperor suggestion but it just worked for a few minutes.

I'm having the same issue, but the suggestion xemperor give us worked for me.