On page URL error with www but not with https://

I often cross link in my posts from one page on my site to another - like anyone would do.

I’ve noticed that if I type in the link and only have


then when the post is published and you go to click on that link it will have


Does anyone know how to fix this, other than making sure I type in https://www.cut-daily.com/url-i’m-linking-to/ (so not forgetting the https:// )