We implemented a simple servlet application with oidc, and used wildfly 26 as runtime. Deeplinking is not working.
when we do a reqeust to the application e.g.
http://localhost:8085/example?var=value
we would expect that we would be redirected to our keycloak server (http://localhost:8080) like this:

http://localhosts:8080/auth/realms/myreal/protocol/openid-connect/auth?response_type=code&client_id=baloise-oidc-example-app&redirect_uri=http%3A%2F%2Flocalhost%3A8085%2Fexample%3Fvar%3Dvalue&state=12345434&scope=openid

but we get this:
http://localhosts:8080/auth/realms/myreal/protocol/openid-connect/auth?response_type=code&client_id=baloise-oidc-example-app&redirect_uri=http%3A%2F%2Flocalhost%3A8080%2Fexample&state=12345434&scope=openid

you see the missing query parameters.
After a successful login with keycloak we would expect
http://localhost:8085/example?var=value
but we get
http://localhost:8085/example/

Our application is running on port 8085 and keycloak on port 8080.
I added the app jbossapp.zip

Problem seems to be located here:

https://github.com/wildfly-security/wildfly-elytron/blob/1.x/http/oidc/src/main/java/org/wildfly/security/http/oidc/OidcRequestAuthenticator.java#L386-L388

Query parameters are not taken in account.