This article documents a known behavior where Message Boards' CKEditor—when configured to HTML—will have text stripped from hyperlinks after a post. This is usually observed after setting the protocol to Other.
Resolution
This behavior is expected under Liferay DXP's Antisamy configuration. The accepted out-of-the-box (OOTB) protocol options for Other include HTTP, HTTPS, FTP and NEWS. Other OOTB options, such as relative paths (e.g., /web/guest/home), can be used to link to internal pages or assets.
Please keep in mind that while this is the default OOTB behavior in a stock Liferay instance, Antisamy can be configured or customized to your liking.
For more information, please visit our AntiSamy guide. Also be aware that disabling or changing an AntiSamy configuration improperly may expose your Liferay environment to potential security vulnerabilities. With this being said, please proceed at your own risk if any adjustments are necessary.