I have scrolling problems very often with the calendar app on macOS.
It works "a bit" but get stuck into the current week, scrolling left or right will just bump but not scroll, driving me insane.
You can see something about that here: https://discussions.apple.com/thread/7954399
Although the solution enunciated there works, it's very inefficient and boring procedure to do.
Best Answer
A stupid and so simple solution, which for months (if not years...) I didn't think about, is simply to right click in the calendar app (with the same two fingers you use to scroll).
And that's it, problem gone!