Why Are Pull Requests Not Triggering Builds On A Multibranch Project?

New pull requests from SCMs (GitHub, Bitucket, etc.) do not trigger a new build for multibranch projects.

If the Basic Branch Build Strategies Plugin is installed and configured, all PR events will be skipped if the "Skip initial build on first branch indexing" setting is enabled. There is an open issue that can be tracked follow a fix for the plugin.

Removing the "Skip initial build on first branch indexing" option for the multibranch project will allow PR builds to work again.