IOS version 7.1.2 has a calendar bug that is showing certain regions incorrect holidays. The bug is causing certain regions to experience the issue areas such as the United States, United Kingdom, and Russia are working accordingly.
The bug was discovered by a user in Lithuania who has the wrong holidays being shown some of the holidays listed are in Hong Kong, Mexico and other various regions. The issue has been recognized by Apple and they announced the issue was going to be fixed in the next patch, and the issue is who knows when that is going to happen.
The bug was recently brought to life in version 7.1.2 so who knows when the bug is going to be fixed but if you are experiencing the issue please report it to Apple and then the update is likely to come sooner. Or it will be issued in what is known as a hotfix which is normally a quick unscheduled patch that is meant to fix a critical issue in the software which I honestly doubt Apple will do over this issue.
The bug is a minor issue but it can be quite annoying if you are experiencing the issue for now I recommend that you use another calendar service or if you are curious about the holidays look them up via Google or use some sort of alternative means to find them. They do still print calendars so if you have one lying around some where you can use that.
Below is a video of the bug and proof that it is existing thank you to the uploader and thank you for submitting this issue to Apple so we can get a fix to it as soon as possible.