I used to have my anniversary in my personal contact in my Google address book. This also showed up in the birthday calendar on Android P and also the web version. As the anniversary does not apply any more, I have removed it from my contact. It does not show up any more on the web Google calendar.
However it keeps being shown in the Android version, also on the widget of my home screen. I have tried letting the calendar app refresh twice, I have closed it via the launcher. It hurts every time I see it. Is there some way to make this calendar entry go away?