These things are ripe for false flag operations. That's been a standard in Portland for at least the past 2 years, when Proud Boys and a few other right-wing people have dressed as antifa and incited violence.

This past weekend, a notorious Proud Boys member, out on parole for doing exactly that, was quite prominent in the crowd of violent "protesters." They use the pretext of the protests to be violent.
Here's a WaPo article about it. I realize it's easy to dismiss WaPo, but from what I can see this article is pretty factual, just ignore the quotes from the people on the street.

Here's how OPB (our local PBS station) covered things.