Over 130 blank notes (and some with dots) in iOS notes

I discovered over a hundred and thirty new handwritten notes in my iCloud iOS Notes. Most of the notes were blank, but many of them had random blue dots throughout.

The first note had a busy pattern of blue dots (and a single line) that look like this:

The next one had four, and the others had one or two random dots.

This happened was when I was away on a trip, and I'm very careful about using sensitive information on the hotel WiFi, so I usually just do some boring scrolling and reading before bed. I thought that I may have been dozing and accidentally created the notes, but when I checked the time stamps, all 130+ notes happened within a 6-minute period. Also, I don't think that someone dozing could create such uniform rows of dots.

Has anything weird like this happened to anyone else?