It could show little professionalism from the consultant, but let's not rush into conclusions.
I can't see no "code from my end" that they couldn't see on a published website using developers tools, to begin with.
Your client should be told that. And there's a professional way to do it: first ask to be told by the consultant exactly what they need to know, where they think they can find that information, and why they can't find that on the staged website.
Web marketing and SEO are good, they are needed, they are effective. But there is a gaziliion ways to handle that, and among them some are disputable. I've been very skeptical about the entire SEO domain for years because of people not being able to explain or demonstrate the benefits they'll bring to their clients. I had to wait meeting people that have a honest and comprehensive approach to be convinced and I have now SEO specialists around me that I can count on and do a great and humble job.
Marketing and SEO are difficult to understand for clients and designers, most of the time. There's also a chance that your client didn't transfer the information clearly and that the Hubspot consultant is absolutely honest and professional. So don't rush in conclusions and try to sort that out as politely as you can