Modeshape REST gives null pointer exception response to JCR SQL2 query

Hello, Hello I'm using Modeshape 5.4.1 and the REST API, modeshape-web-jcr-rest-war, to support both direct Get/Put/Post operations for content nodes, as well as through JCR SQL2.

I've noticed that sometimes ModeShape or the REST API gets into a state where any JCR SQL2 query (via POST) will result in a null pointer exception.

Restarting Modeshape is the only thing that currently seems to resolve the issue. Has anyone else encountered this behavior?

DEBUG o.m.w.jcr.rest.filter.LoggingFilter - Received request: http://bogus.davidbharrison.com/modeshape-psi/*rest/repo/default/query*

DEBUG o.m.w.jcr.rest.filter.LoggingFilter - Executing method: POST
DEBUG org.modeshape.jcr.query - There are several warnings with this query: SELECT [nt:unstructured].[mode:uri] FROM [nt:unstructured]

(Note, this warning does not stop the JCR SQL2 query from running, normally)
WARNING: Column 'mode:uri' does not exist on the table 'nt:unstructured'. Verify that you intended to reference a residual property.

DEBUG o.m.w.j.rest.handler.AbstractHandler - Logged out REST service session
ERROR o.m.w.j.r.ModeShapeExceptionMapper - Server error java.lang.NullPointerException: null