There is a bug in copy and paste for rich text using links.
If you copy a rich text containing a link within your website and the link has been built using page name (not URL), then when you paste, your site name will be replaced by www.webflow.com/your collection…
I have experienced issues for links getting wild for weeks ( I am afraid since July). Just discovered what it was a few days ago… Webflow said they were going to check but no news.
So please check your links after copy and paste.
Now I am checking link by link across the 1000 pages on my website…
This is what kind of link you are getting after a copy and paste: