Tagging the author in your video?

What is the etiquette of tagging the author in your book review videos? I recently made my first book review video, and I tagged the author in the short version of the video on Instagram. He untagged himself and ignored the long form video on youtube.

I made an 11.5 minute long, really complimentary video, about a book that was very recently shortlisted for a conservation writing prize in England. The winner has not yet been announced. My channel is normally about my conservation actions, so I used b-roll of cleaning up litter from a wetland with voiceover for my review instead of just my face looking at the camera. I had kind of assumed it would be ok to tag him, because he is currently trying to gain momentum for the book before the winner of the prize is announced. Also, people are seldom offended by videos about picking up litter, especially conservationists! But the author untagged himself from the short version of the video and has entirely ignored the long version. I just wanted to check if I crossed a line by tagging him? Do people making book review videos usually tag the authors?

He has posted a couple of recent Instagram stories about how his book is receiving less attention than the others shortlisted and wondering if it is because he is neurodivergent. The book is published by Bloomsbury, so it's not exactly unheard of! But, my video is currently the only one reviewing it on youtube, and my review is on the first page of google when you search for the book's title. He has not asked me to take it down, but it is my worst performing video by a looooong way, so I could take it down if it's not ok.