Site url added to links

Hello,

Today I was cleaning up old links on my site and noticed somehow the site url gets tacked on in front of the url I’m making a link of.

No changes, no new plugins or anything..just out of now where. Trying to link an image or text and when previewed or live the link is there, only with the website url in front of it…messing it up. Cant edit it out though in the post dashboard lol

Would anyone know why?

thanks!