All requests to the SDATA schema URL using the hostname return an error 400 (Bad Request).
Requests to localhost work correctly:

• http://localhost/sdata/default.aspx?r=/sdata/test.html
• http://localhost:[Tomcat Port]/[CRM Install Name]j/sagecrm/-/$schema
• http://localhost/sdata/[CRM Install Name]j/sagecrm/-/$schema


The issue would occur either when connecting via the SDATA rewriter, or directly when connecting to the Tomcat web server, indicating an issue within Tomcat.

Work around / Resolution:

The Catalina engine hostname in the \CRM\tomcat\conf\server.xml was set to the machine's name rather than localhost.
The correct entry should read as follows:

<Engine name="Catalina" defaultHost="localhost">