I have noticed this as well. Hard to predict human behavior. I suspect the follow button is a UI problem. Hopefully, some of the upcoming Medium app changes will help improve.

Newbies often do not understand some of the less intuitive features such as following a writer vs following a pub and signing up for a newsletter.

I am often surprised some authors do not engage or support the other authors for the same publication. They are under no obligation, but there are multiple reasons to interact and support the pub publishing your work.

Supporting authors in your pub motivates them to check out your content. Following other authors in your niche often amplifies your visibility.

Keeping your editor happy never hurts either :) As the editor for Being Well, I like to see our writers reading, clapping, commenting and interacting with other writers on the pub. Using the Illumination concept of cross pollination, this is how we all grow.

The more you give, the more you receive.