WSO2 Identity Server multiple callback URLs breaks checksession endpoint - wso2

Question

I'm having an issue configuring multiple callback urls for a Service Provider in WSO2 Identity Server. This process is necessary for my team to support SLO (Single Logout) with a post logout redirect url.
Callback URL Configuration
The WSO2 online documentation describes the correct way to do this process here. I have followed those step and configured my Callback URL as follows:
regexp=(http://localhost:8080/login-callback|http://localhost:8080/logout-callback)
This process works, and I am able to configure the two Callback URLs.
Unintended "checksession" Side Effect
Once the callback urls are configured, the checksession endpoint stops working. The error message I get from the endpoint says "Invalid OP IFrame Request". That checksession call uses a url like this: https://<wso2host>/oidc/checksession?client_id=<clientid>
I verified that the checksession endpoint works if I configure either of my redirect urls individually
http://localhost:8080/login-callback
http://localhost:8080/logout-callback
But fails if I use the regexp syntax. Failure occurs in each of these scenarios:
regexp=(http://localhost:8080/login-callback|http://localhost:8080/logout-callback)
regexp=(http://localhost:8080/login-callback)
regexp=(http://localhost:8080/logout-callback)
Am I missing a configuration step needed for either the callback urls or the checksession endpoint?

Answer 1

I ended up finding the solution from a hint in the WSO2 logs.
When multiple callback urls are defined, the request for the checksession endpoint must specifiy a callback url as well. The correct checksession reqeust for my scenario was:
https://<wso2host>/oidc/checksession?client_id=<clientid>&redirect_uri=<redirecturi>