Thanks very much Dihao, here's the info you requested.
1: Does this scenario occurs in all SharePoint sites with their default Home pages or this particular SharePoint site?
2: You can also try to create a new SharePoint sites and see whether you can see Home.aspx page is listed under Site pages in Site usage.
I only had one SharePoint site so was unable to answer no1. I created a new site and the same thing happened. My new site had a Home page and one extra page. I could see counts on the extra page, but not on the system generated Home page.
3: Try to switch to a different browser and see the results.
Edge: My default browser. This occurs
Chrome: Same thing
Int Explorer: Site Usage Report was not generated at all.
4: How about the other colleagues with their own SharePoint site in your organization tenant? Do they have the same scenario when they view the home page in SharePoint Usage?
I checked with another SharePoint site owner and they have the same issue.