I turned on Debug logging for the Shibboleth `idp-process` and got a bit more info but nothing that's meaningful for me.
```
2017-06-22 11:33:30,263 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:154] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler of type 'org.opensaml.saml.common.binding.impl.CheckMessageVersionHandler' on INBOUND message context
2017-06-22 11:33:30,266 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:175] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler on message context containing a message of type 'org.opensaml.saml.saml2.core.impl.AuthnRequestImpl'
2017-06-22 11:33:30,266 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:154] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler of type 'org.opensaml.saml.saml1.binding.impl.SAML1ArtifactRequestIssuerHandler' on INBOUND message context
2017-06-22 11:33:30,266 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:175] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler on message context containing a message of type 'org.opensaml.saml.saml2.core.impl.AuthnRequestImpl'
2017-06-22 11:33:30,267 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:154] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler of type 'org.opensaml.saml.common.binding.impl.SAMLProtocolAndRoleHandler' on INBOUND message context
2017-06-22 11:33:30,267 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:175] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler on message context containing a message of type 'org.opensaml.saml.saml2.core.impl.AuthnRequestImpl'
2017-06-22 11:33:30,268 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:154] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler of type 'org.opensaml.saml.common.binding.impl.SAMLMetadataLookupHandler' on INBOUND message context
2017-06-22 11:33:30,268 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:175] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler on message context containing a message of type 'org.opensaml.saml.saml2.core.impl.AuthnRequestImpl'
2017-06-22 11:33:30,268 - INFO [org.opensaml.saml.common.binding.impl.SAMLMetadataLookupHandler:128] - Message Handler: No metadata returned for https://myredactedurl.com/moodle/auth/saml2/sp/metadata.php in role {urn:oasis:names:tc:SAML:2.0:metadata}SPSSODescriptor with protocol urn:oasis:names:tc:SAML:2.0:protocol
2017-06-22 11:33:30,268 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:154] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler of type 'org.opensaml.saml.common.binding.impl.SAMLAddAttributeConsumingServiceHandler' on INBOUND message context
2017-06-22 11:33:30,269 - DEBUG [net.shibboleth.idp.profile.impl.WebFlowMessageHandlerAdaptor:175] - Profile Action WebFlowMessageHandlerAdaptor: Invoking message handler on message context containing a message of type 'org.opensaml.saml.saml2.core.impl.AuthnRequestImpl'
2017-06-22 11:33:30,269 - DEBUG [net.shibboleth.idp.saml.profile.impl.InitializeRelyingPartyContextFromSAMLPeer:132] - Profile Action InitializeRelyingPartyContextFromSAMLPeer: Attaching RelyingPartyContext based on SAML peer https://myredactedurl.com/moodle/auth/saml2/sp/metadata.php
2017-06-22 11:33:30,271 - DEBUG [net.shibboleth.idp.relyingparty.impl.DefaultRelyingPartyConfigurationResolver:293] - Resolving relying party configuration
2017-06-22 11:33:30,271 - DEBUG [net.shibboleth.idp.relyingparty.impl.DefaultRelyingPartyConfigurationResolver:299] - Profile request is unverified, returning configuration shibboleth.UnverifiedRelyingParty
2017-06-22 11:33:30,271 - DEBUG [net.shibboleth.idp.profile.impl.SelectRelyingPartyConfiguration:136] - Profile Action SelectRelyingPartyConfiguration: Found relying party configuration shibboleth.UnverifiedRelyingParty for request
2017-06-22 11:33:30,272 - WARN [net.shibboleth.idp.profile.impl.SelectProfileConfiguration:111] - Profile Action SelectProfileConfiguration: Profile http://shibboleth.net/ns/profiles/saml2/sso/browser is not available for relying party configuration shibboleth.UnverifiedRelyingParty
2017-06-22 11:33:30,277 - WARN [org.opensaml.profile.action.impl.LogEvent:76] - An error event occurred while processing the request: InvalidProfileConfiguration
```