I noticed that that the BLM protests happened a few months before the 2016 election and then vanished. Then the same thing happened before the 2020 election.
To make this quantitative, here's a Google Trends link: https://trends.google.com/trends/explore?date=today%205-y&ge...
Protests are not necessarily “newsworthy”; however, that search interest would track media stirring up news before elections seems likely.
Further, (and I say this as a Minneapolitan) the significant protests of this summer were very clearly and obviously precipitated by real world events, not astroturfed protest crowds.
I would surmise that a lot of the protests this summer were, emotionally, a consequence of the stress, economic uncertainty, and way-too-online cabin fever of the early stages of the COVID epidemic.