Server Redirected URL

Is it possible to stop a site home page going through the server re-direct? 

Background

We created multiple Teams via Teams. The SharePoint site home pages for all except one of these sites work fine. 

On one of the sites, when you click on 'Home', it first opens the site name URL address (sites/sitename), then you see '?sw=auth' briefly, then it opens 'sites/sitename/sitepages/home.aspx'. 

Curiously, this happens every second time you click on 'Home', not every time. 

Why is this re-direct happening? 

Investigation

On each of the good sites, the page source shows 'serverRedirectedUrl' is the full URL of the site home page (https:// ... home.aspx). 'serverRequestPath' shows the same from '/sites ... home.aspx'. BUT, on the page with the problem, 'serverRedirectedUrl' is ':null,'. 

We followed guidance that suggested to create new page and make that the home page. That one also has the re-direct, which is fine. Then we made the 'old' home page (home.aspx) the homepage again but the problem is still there. Every second click of 'Home' does the re-direct. 

It's not possible to edit the source code of the site so we cannot insert the home page address after 'serverRedirectedUrl'. 

Anyone have any suggestions, aside from deleting (and then force-deleting) the team/group/site and starting again? Ideally need an answer to this before 10 June 2022. Thanks in advance.