Help me have consistent short URLs

I think URLs matter and I prefer neat ones.

I’m experiencing a weird bug on our Intranet and cannot figure out why this is happening.

Everytime I click on one of the menu items the URL shows slightly differently.

We have several portals (Team Sites) linked from our Hub Navigation:

Figure: Each item links to a different portal, i.e. https://sswcom.sharepoint.com/sites/XXX

Every single link is setup using the short URL form – i.e. not linking directly to the aspx page.

However, sometimes/often/randomly, when clicking one of the menu items, the URL is somehow rewritten to https://sswcom.sharepoint.com/sites/XXX/SitePages/Home.aspx

Figure: URL being randomly rewritten to the “full” form (i.e. full page’s path)

Moreover, clicking the Site’s “home” tile (i.e. Site Logo) will almost always toggle – yes toggle – between the two URLs… 

I have noticed that, before it flicks to the “long” form, there is a weird querystring parameter being added for a split second, and then the rewrite happens:

Figure: Weird “sw=auth” querystring parameter
  1. Can you please explain what is causing the issue?
  1. How do we fix it? 
    We want to be using the “short” form as much as possible