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:
./gradlew clean run
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"
"active": true // other claims omitted}
From: cf-dev@... <cf-dev@...> on behalf of Shetty, Viraj S [CTR] via lists.cloudfoundry.org <vshetty=fdic.gov@...>
Sent: Friday, September 11, 2020 12:44 PM
To: cf-dev@... <cf-dev@...>
Subject: Re: [cf-dev] UAA api /introspect does not seem to be workign as expected #uaa
I upgraded to the latest UAA version 74.24.0 and I still see the same issue. Is there something I can provide from logs that might help ?