Do you have any examples of this? I've re-read the posts leading up to the draft here, on reddit, hockeynews, and other similar prospect ranking sites. It was Nolan Patrick and Hirschier considered 1/2 and then a crap shoot after that. In fact, Makar wasn't in top 5 in most of them until literally like a month before the draft. (Pronman had him at 18 as late as June 19th, ouch).
2017 NHL draft rankings. A compilation of the top NHL draft prospects rankings for the 2017 draft from a variety of NHL scouting service and media outlets.
www.mynhldraft.com
I do remember Colorado saying they had him as the #1 ranked prospect years later (which may or may not be true), but nothing that had him close to 1 before the draft.