You may have noticed that sharing any URL links will be disabled in some instances when replying to a post. There is a work around that will allow you to share links to screenshots, videos, and replays.
You can use either the Preformatted text option (the button with </>) or the Blockquotes button ("). It will display the link as shown in the examples below:
(Preformatted Text) https://www.playhearthstone.com
(Blockquotes) https://www.playhearthstone.com