Unsatisfied Entitlements: NSEndpointSecurityMachServiceName error

After adding the NSEndpointSecurityMachServiceName entitlement to my SYSEX's entitlements file and trying to install and load it on 10.15.6 and 11 beta 6, I get the following errors:

error 15:03:48.715632-0400 taskgated-helper <bundle id>: Unsatisfied entitlements: NSEndpointSecurityMachServiceName
error 15:03:48.715655-0400 taskgated-helper Disallowing: <bundle id>
default 15:03:48.716927-0400 amfid /Applications/<app name>/Contents/Library/SystemExtensions/<bundle id>.systemextension/Contents/MacOS/<bundle id> signature not valid: -67671
default 15:03:48.719367-0400 ReportCrash Parsing corpse data for process <bundle id> [pid 985]
default 15:03:48.717099-0400 kernel proc 985: load code signature error 4 for file "<bundle id>"
default 15:03:48.717768-0400 kernel Security policy would not allow process: 985, /Applications/<app name>/Contents/Library/SystemExtensions/<bundle id>.systemextension/Contents/MacOS/<bundle id>

The host app and SYSEX are both signed and notarized with a Developer ID certificate that contains the com.apple.developer.endpoint-security.client entitlement and the appropriate provisioning profile. The host app and SYSEX both have the hardened runtime enabled, but with Code Signing Inject Base Entitlements off for release builds.

Thoughts?

Thanks in advance!