Is there a particular way professional writers read their work out loud to the pubic?

In this past month I’ve been to two book signing/readings by different authors. The first time I went, the author read their writing (it was fiction) with kind of a serious and slightly monotone voice. I thought this was kind of odd, because I’m used to hearing and reading stories with more energy and dynamics, but I just thought it was probably that specific author who wanted to read in that way.

But then, just recently I went to another reading with my boyfriend, and this author was doing the same thing! Is this normal, or just a coincidence that they sounded the same? I don’t know much about the professional writing world, so maybe I’m observing something that’s pretty typical. Idk

Can anyone shed some light on this? thanks :)