Quick Launch links - Repeating parameters in query string

I am using SharePoint online. Site Collection was created off the Team Site template and I have enabled the Publishing feature.

I have noticed some strange behaviour when creating links in the Quick Launch. Where the links have parameters in the query string Ie.https://domain.sharepoint.com/site/library/document.pdf?Web=1, these are working, but after a while (and I can't identify what is causing this to change), the link changes, with the parameter repeated multiple times Ie. https://domain.sharepoint.com/site/library/document.pdf?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1?Web=1.....

Has anyone else experienced this behaviour?

Thanks in advance!