Delphi, C++Builder and RAD Studio 11.3 have now a patch available for download in GetIt, with the Welcome page alerting of the patch. 

You can read more in the official announcement at https://blogs.embarcadero.com/rad-studio-11-3-alexandria-patch-1-available/

I recommend installing it, given it addressed a few relevant issues with REST requests and dataset operations, among others. The list of quality portal issues addressed is in the blog post above.