Sharepoint logo not changing

So I have recently learned that if you have a mix of Sharepoint Modern and Sharepoint Classic view pages, changing the site logo under the classic page will not proliferate to the modern page.  But the reverse will cascade the change through all pages.

So what I mean is, the site logo will not change unless you make the change as follows:

Gear-->Change the look-->Header-->scroll down-->Site logo-->upload here.

If you attempt to change from here:

Site Settings-->Title, description, and logo-->Insert Logo  

and that is a Sharepoint classic themed page, it will not change.

Image type does not matter, for example, I am using a .gif and it is working fine.

Thanks,

Farrell