CAS OOB exception

I originally posted about this on the shib-users list - https://marc.info/?l=shibboleth-users&m=155871157406298&w=2

We're trying to configure a CAS SP.

Acc'd to the logs, the (sanitized) entityID is "https://testing.vialivetext.com/auth/cas/callback?organization_id=12345678abc&redirect_url=&url"

It ignores the metadata, and drops back to the service registry (where I did add appropriate regex for their hostname). When the IDP fields the authn request, it returns an OOB exception

Here's the applicable configuration.

metadata-providers.xml:
<MetadataProvider id="cas" xsi:type="FilesystemMetadataProvider" indexesRef="shibboleth.CASMetadataIndices" metadataFile="%{idp.home}/metadata/cas.xml"/>

cas.xml:
<EntityDescriptor entityID="https://testing.vialivetext.com/auth/cas/callback" xmlns="urn:oasis:names:tc:SAML:2.0:metadata">
<SPSSODescriptor protocolSupportEnumeration="https://www.apereo.org/cas/protocol">
<SingleLogoutService
Binding="https://www.apereo.org/cas/protocol/logout"
Location="urn:mace:shibboleth:profile:CAS:logout"/>
<AssertionConsumerService
Binding="https://www.apereo.org/cas/protocol/login"
Location="https://testing.vialivetext.com/auth/cas/callback"
index="1"/>
</SPSSODescriptor>
</EntityDescriptor>

Acc'd to the logs, it seems to load ok.
2019-05-31 14:20:25,444 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:350] - - Metadata Resolver FilesystemMetadataResolver cas: Beginning refresh of metadata from '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml'
2019-05-31 14:20:25,445 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:357] - - Metadata Resolver FilesystemMetadataResolver cas: Processing new metadata from '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml'
2019-05-31 14:20:25,446 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:487] - - Metadata Resolver FilesystemMetadataResolver cas: Unmarshalling metadata from '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml'
2019-05-31 14:20:25,467 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:531] - - Metadata Resolver FilesystemMetadataResolver cas: Preprocessing metadata from '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml'
2019-05-31 14:20:25,468 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractMetadataResolver:376] - - Metadata Resolver FilesystemMetadataResolver cas: Applying metadata filter
2019-05-31 14:20:25,532 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:541] - - Metadata Resolver FilesystemMetadataResolver cas: Releasing cached DOM for metadata from '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml'
2019-05-31 14:20:25,532 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:545] - - Metadata Resolver FilesystemMetadataResolver cas: Post-processing metadata from '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml'
2019-05-31 14:20:25,533 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:549] - - Metadata Resolver FilesystemMetadataResolver cas: Computing expiration time for metadata from '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml'
2019-05-31 14:20:25,534 - DEBUG [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:554] - - Metadata Resolver FilesystemMetadataResolver cas: Expiration of metadata from '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml' will occur at 2019-05-31T22:20:25.444Z
2019-05-31 14:20:25,534 - INFO [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:574] - - Metadata Resolver FilesystemMetadataResolver cas: New metadata successfully loaded for '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml'
2019-05-31 14:20:25,535 - INFO [org.opensaml.saml.metadata.resolver.impl.AbstractReloadingMetadataResolver:384] - - Metadata Resolver FilesystemMetadataResolver cas: Next refresh cycle for metadata provider '/usr/local/mcomm/shibboleth-idp/metadata/cas.xml' will occur on '2019-05-31T21:20:25.466Z' ('2019-05-31T17:20:25.466-04:00' local time)

I want to use metadata, but since it seems to want to use the service resigstry, for testing purposes, I made the rules in cas-protocol.xml fit vendor's hostname...
<bean id="reloadableServiceRegistry"
class="%{idp.cas.serviceRegistryClass:net.shibboleth.idp.cas.service.PatternServiceRegistry}">
<property name="definitions">
<list>
<bean class="net.shibboleth.idp.cas.service.ServiceDefinition"
c:regex="https://([A-Za-z0-9_-]\.)*vialivetext\.org(:\d)?/.*"
p:group="proxying-services"
p:authorizedToProxy="true"
p:singleLogoutParticipant="true" />
<bean class="net.shibboleth.idp.cas.service.ServiceDefinition"
c:regex="http://([A-Za-z0-9_-]\.)*vialivetext\.org(:\d)?/.*"
p:group="non-proxying-services"
p:authorizedToProxy="false" />
</list>
</property>
</bean>

And the IDP is throws the OOB..
2019-05-31 14:23:58,935 - DEBUG [net.shibboleth.idp.cas.flow.impl.BuildRelyingPartyContextAction:103] - x.x.x.x - Querying net.shibboleth.idp.cas.service.impl.MetadataServiceRegistry for CAS service URL https://testing.vialivetext.com/auth/cas/callback?organization_id=1234567890abc&redirect_url=&url
2019-05-31 14:23:58,951 - ERROR [net.shibboleth.idp.cas:-2] - x.x.x.x - Uncaught runtime exception
java.lang.ArrayIndexOutOfBoundsException: 1
at net.shibboleth.utilities.java.support.net.URLBuilder.<init>(URLBuilder.java:119)
2019-05-31 14:23:58,977 - WARN [org.opensaml.profile.action.impl.LogEvent:105] - x.x.x.x - A non-proceed event occurred while processing the request: RuntimeException
2019-05-31 14:23:59,021 - INFO [Shibboleth-Audit.SSO:275] - x.x.x.x - 20190531T182359Z||||https://www.apereo.org/cas/protocol/login|||||||||

I'm not sure what else to try. The configuration options from the vendor are very limited.