GitHub and Bitbucket show different behavior w.r.t. re-evaluation of pull requests:

1. GitHub PRs are rebuilt after their target branch is updated;
2. Bitbucket PRs are not rebuilt after their target branch is updated.

I find the GitHub behavior quite useful for early detection of incompatibilities between work of multiple developers.

Although I am aware of the controversy around this behavior, I would really appreciate if Jenkins multi-branch pipelines behave in the same way for major git server vendors.