when creating links (e.g. abc.xyz) using the markdown-editor and the Hyperlink-button, I frequently end up with something like this: [] (abc.xyz); and of course this does not work.
In the WYSIWYG-editor & the Hyperlink-button, when adding the same link, I end up with abc.xyz, which does not work either (even produces an error message).
As you can see, leaving the first part blank will make the link disappear.
Because you seem to be comfortable using links like ABC.xyz i would suggest you go into the setting under the markdown section and "enable Linkify" this will make it so that an old link is clickable in the rendered view.