When Bitbucket DC receives an HTTP request containing invalid characters in the request target (for example, an unencoded | or other reserved characters in the Create Branch URL), Tomcat rejects the request with HTTP 400 – Bad Request in accordance with RFC 3986 / RFC 7230.

However, in this scenario Bitbucket DC displays Tomcat’s default HTTP 400 error page instead of a Bitbucket-branded error page with a clear, actionable message. This results in a poor user experience, especially when triggered indirectly via the “Create branch” action from Jira Cloud.

Expected:
Bitbucket should show a Bitbucket error page for HTTP 400 cases with a clear explanation that the request URL contained invalid characters and, where possible, guidance on how to resolve it.

Actual:
Users see Tomcat’s default “HTTP Status 400 – Bad Request” page, with no Bitbucket context or guidance.