The build now action in Bitbucket (see below) can't be initiated in Bitbucket Server Integration Plugin 4.1.4.

I believe this is because version 4.1.4 fixes Jenkins Security Advisory 2025-01-22. However, CSRF protection is not disabled for this URL.

Jenkins responds with the following:

Bitbucket doesn't have access to the crumb generated by Jenkins in the Jenkins user's session and therefore can't provide it in the Jenkins-Crumb header.

Rolling back the plugin to version 4.1.3 fixes this issue, but doesn't include the security fixes from 4.1.4