Extra calendar component is found in publish summary, when user try to publish first component to page. You can reproduce this issue on remote and local staging.
Steps:
- create new site
- create new page (optional)
- publish changes → everything ok so far (optional)
- add any component to page
- publish changes
- check publish summary → next to your changes, you can find calendar component
Expected result: publish summary should only contain changes issued by user
Actual result: in publish summary you can find extra calendar component
Reproducible: Ubuntu 16.04, Mysql 5.7, nightly 81a03d5432758ff5a03077710851d90e33e20b98 (Tomcat 8.0.32) Firefox ESR, Chrome
Fix priority: S2 + L4 = 3