Charge seems to randomly go up a few points throughout the day

I’ve noticed that on some days my battery goes up a point or two at seemingly random times up to a few times a day. I’m not taking naps nor does my watch think I’m sleeping—any idea why this happens? The graph doesn’t show a charging indicator for these either.

In the video you can see it went back up 49 to 50, 40 to 41, and 39 to 40.