Comment 2 for bug 1866999

I'm not seeing that problem here as an item that I changed elsewhere earlier today does show in its revised form in gnome-calendar.

Does "Synchronise Calendars" on the "Manage on your calendars" menu help to resolve the issue?

FWIW, while composing this reply I changed an item in Google Calendar, clicked on "Synchronize Calendars" and the amended details were displayed immediately.