It seems changes related to dev changes, changed expected type of the Princiapl set during authentication from java.security.Principal to com.atlassian.confluence.security.seraph.ConfluenceUserPrincipal

The authentication process for Trusted Apps links was updated for this by adding a com.atlassian.confluence.security.trust.seraph.ConfluenceSeraphAuthenticationListener which converts the Principal into ConfluenceUserPrincipal.

OAuth was not updated and calls would appear to fail despite the OAuth processing working correctly, see https://ecosystem.atlassian.net/browse/APL-1092