I couldn't replicate the issue you've described.  While logs are always helpful, more helpful would be a small set up replicating the issue. For example, this is what I did to replicate your issue using the UAA in development:

uaac target http://localhost:8080/uaa

uaac token client get admin

uaac client add introspect-test --scope uaa.none --authorized_grant_types client_credentials --authorities uaa.resource

uaac token owner get cf marissa -p koala --scope uaa.user

uaac contexts #extract marissa's access token

uaac token client get introspect-test

uaac curl --trace /introspect -X POST -d "token=marissas-access-token"

200

RESPONSE HEADERS:

<snip>

RESPONSE BODY:

{

  "active": true // other claims omitted