Lightroom CC video tutorials: reverse results obtained when following sample photo instructions

Your post is under the "Lightroom Classic CC" product heading, but you mention "Lightroom CC" in your description.  I know it's confusing, but those are two different products.  Just to be clear, which one are you using/referring to?

No it is not a bug. Look at the Pixel dimensions of the image. I bet it is fairly small, low number of pixels, like 300 x 200 or even smaller.
The Fit View, which is the default view mode of LR, will Zoom a small pixel dimension image to Fit to the Viewing area. When you go to 1:1 that is One pixel of the image to One pixel of the screen. If you are using a screen with a resolution of somewhere around 1900 x 1200, or whatever, then a 300 x 200 pixel image will look Zoomed Out. When in actuality it is being displayed one image pixel to one screen pixel, 1:1.

You're camera is probably set to capture images as JPG format only and you have it set to the lowest resolution.
This is Fit view of a 300 x 450 pixel image.




This is 1:1 of that same image.

I have moved your post to the correct forum.

Thanks Rikk.

Just Shoot Me is probably right with their answer. It's possible the monitor your using is higher resolution than the one being demonstrated on. The same image on a really high resolution screen will not appear to zoom/fill the preview area the same way as on a lower resolution monitor.

Yep! Both of you, Just Shot Me and Jeffrey, are almost completely right! Yes, I do have a new and very high resolution monitor, but the photos used in the tutorials aren't mine. They are sample photos provided in each of the tutorials for practicing. They have to be downloaded in new albums created for that purpose (also a way of practicing this procedure). I am guessing they are old samples or they were created without taking in account very high resolution monitors.
Later, I opened a photo of mine and didn't have any problem zooming in or out. As you say, it gave me proof the sample photos were the problem
For the newcomer, these Lightroom CC basic tutorials are fantastic. Very well done, simple but detailed and easy to follow; a very intelligent way to sweep off Photoshop's fears. But from a new (and very evaluating) customer point of view, this small glitch is not small mistake. It creates anxiety, confusion, delay, and loss of time trying to figure out what's going on. So, hooray for Photoshop!.., but, please, upgrade those tutorial sample photos with ones of higher resolution.