On iPad OS 14.0.1:
Same on every page - a few random icons are smaller than the rest.
Fortunately fixed with a restart 
It’s related to changing your wallpaper. Broad issue. Restart usually fixes until you change your wallpaper again.
yep had not thought of that but I had changed it not long before
I had the same problem with random icons that were smaller than normal and I haven’t changed my wallpaper in years. However, restarting does solve the problem.